Peptide Database
265 therapeutic peptides with research summaries, clinical findings, and regulatory status.
BPC-157
A synthetic gastric pentadecapeptide derived from a protein found in human gastric juice. BPC-157 promotes angiogenesis and the expression of growth factors including VEGF, EGF, and NO-mediated pathways. It has demonstrated cytoprotective and wound-healing properties across multiple tissue types in preclinical models, including tendon, muscle, ligament, and gastrointestinal mucosa.
TB-500 (Thymosin Beta-4)
Thymosin Beta-4 is a 43-amino acid actin-sequestering protein involved in cell migration, differentiation, and tissue repair. It promotes wound healing by upregulating cell-building proteins such as actin and laminin, facilitating cell migration to sites of injury. TB-500 also has anti-inflammatory properties mediated through NF-kB pathway modulation.
GHK-Cu
A naturally occurring copper-binding tripeptide (glycyl-L-histidyl-L-lysine) found in human plasma, saliva, and urine. GHK-Cu activates tissue remodeling by stimulating collagen synthesis, glycosaminoglycan production, and angiogenesis while suppressing fibrinogen synthesis. It modulates the activity of matrix metalloproteinases and influences over 4,000 genes related to tissue repair.
DSIP (Delta Sleep-Inducing Peptide)
A naturally occurring nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) originally isolated from cerebral venous blood of rabbits during induced sleep. DSIP modulates sleep architecture by promoting delta wave (slow-wave) sleep through interactions with the GABAergic system and hypothalamic sleep centers. It also exhibits stress-protective, analgesic, and neuromodulatory properties.
Pentosan Polysulfate (Elmiron)
A semi-synthetic sulfated polysaccharide derived from beechwood hemicellulose with structural similarities to glycosaminoglycans. Pentosan polysulfate replenishes the defective glycosaminoglycan layer of the bladder urothelium in interstitial cystitis, reducing urothelial permeability to irritants. It also exhibits anti-inflammatory, anticoagulant, and fibrinolytic properties through inhibition of complement activation and mast cell histamine release.
Semaglutide (Ozempic/Wegovy)
A glucagon-like peptide-1 receptor agonist (GLP-1 RA) with 94% amino acid homology to native GLP-1. Semaglutide enhances glucose-dependent insulin secretion, suppresses glucagon, delays gastric emptying, and acts on hypothalamic GLP-1 receptors to reduce appetite. Its fatty acid side chain enables albumin binding, extending its half-life to approximately 7 days.
Tirzepatide (Mounjaro/Zepbound)
A first-in-class dual glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonist. Tirzepatide activates both incretin pathways simultaneously, producing superior glycemic control and weight loss compared to selective GLP-1 RAs. The dual mechanism enhances insulin sensitivity and lipid metabolism beyond what either pathway achieves alone.
Retatrutide
An investigational triple hormone receptor agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. The glucagon receptor component adds thermogenic energy expenditure and hepatic lipid mobilization to the incretin-mediated appetite suppression and insulin sensitization. This triple mechanism addresses obesity through complementary metabolic pathways.
AOD-9604
A modified 16-amino acid fragment (amino acids 176-191) of the C-terminus of human growth hormone with an added tyrosine at the N-terminus. AOD-9604 retains the lipolytic activity of hGH without its growth-promoting or diabetogenic effects. It stimulates lipolysis and inhibits lipogenesis through a mechanism distinct from the GH receptor, acting on beta-3 adrenergic receptors in adipose tissue.
Liraglutide (Saxenda/Victoza)
A GLP-1 receptor agonist with 97% homology to native GLP-1, modified with a fatty acid side chain (C-16 palmitoyl) enabling albumin binding and a half-life of approximately 13 hours. Liraglutide enhances glucose-dependent insulin secretion, suppresses glucagon, delays gastric emptying, and promotes satiety through hypothalamic GLP-1R activation. It was the first GLP-1 RA approved for chronic weight management.
Exenatide (Byetta/Bydureon)
A synthetic version of exendin-4, a 39-amino acid peptide originally isolated from the saliva of the Gila monster lizard (Heloderma suspectum). Exenatide shares 53% homology with human GLP-1 and is resistant to DPP-4 degradation. It activates GLP-1 receptors to enhance insulin secretion, suppress glucagon, slow gastric emptying, and promote beta-cell preservation.
Glucagon
A 29-amino acid peptide hormone produced by alpha cells of the pancreatic islets of Langerhans. Glucagon acts primarily on hepatocytes via the glucagon receptor (GCGR), a G-protein-coupled receptor that activates adenylyl cyclase, increasing cAMP and triggering glycogenolysis and gluconeogenesis to raise blood glucose. It also relaxes smooth muscle of the GI tract and has positive inotropic and chronotropic cardiac effects.
Pramlintide (Symlin)
A synthetic analog of amylin (islet amyloid polypeptide), a 37-amino acid peptide hormone co-secreted with insulin from pancreatic beta cells. Pramlintide has three proline substitutions that prevent amyloid fibril formation while retaining amylin receptor activity. It slows gastric emptying, suppresses postprandial glucagon secretion, and promotes satiety via area postrema activation, complementing insulin therapy in diabetes management.
Dulaglutide (Trulicity)
A long-acting GLP-1 receptor agonist consisting of a GLP-1 analog covalently linked to a modified human IgG4 Fc fragment via a peptide linker. This fusion protein design increases molecular size to reduce renal clearance and enables FcRn-mediated recycling, producing a half-life of approximately 5 days suitable for once-weekly dosing. Dulaglutide activates pancreatic GLP-1 receptors to enhance glucose-dependent insulin secretion and suppress glucagon.
Lixisenatide (Adlyxin)
A selective GLP-1 receptor agonist derived from exendin-4 with a modified C-terminal tail containing six lysine residues. Lixisenatide has a half-life of approximately 3 hours and primarily reduces postprandial glucose through potent delay of gastric emptying rather than fasting glucose reduction. It is designed for once-daily use as an add-on to basal insulin therapy in type 2 diabetes.
Setmelanotide (Imcivree)
A cyclic peptide melanocortin-4 receptor (MC4R) agonist designed to restore MC4R signaling in patients with obesity caused by genetic deficiencies in the leptin-melanocortin pathway. Setmelanotide bypasses upstream defects in POMC, PCSK1, or LEPR genes by directly activating MC4R, reducing hunger and increasing energy expenditure. It represents one of the first precision medicines for genetically defined obesity.
CJC-1295
A synthetic analog of growth hormone-releasing hormone (GHRH) with a Drug Affinity Complex (DAC) that binds to albumin, extending its half-life from minutes to approximately 6-8 days. CJC-1295 stimulates pulsatile GH release from the anterior pituitary by binding to GHRH receptors while preserving the natural GH secretory pattern and negative feedback mechanisms.
Ipamorelin
A highly selective growth hormone secretagogue that acts on ghrelin/GHS receptors in the pituitary gland to stimulate GH release. Unlike other GH secretagogues, ipamorelin does not significantly affect ACTH, cortisol, or prolactin levels, making it one of the most specific GH-releasing peptides. It works synergistically with GHRH analogs like CJC-1295.
Sermorelin
A synthetic 29-amino acid analog of GHRH representing the shortest fully functional fragment of the native 44-amino acid hormone. Sermorelin stimulates the pituitary to produce and release growth hormone through the natural GHRH receptor pathway, preserving the hypothalamic-pituitary feedback axis. It maintains physiological pulsatile GH secretion patterns.
Tesamorelin (Egrifta)
A synthetic GHRH analog consisting of the 44-amino acid sequence of human GHRH with a trans-3-hexenoic acid modification at the N-terminus to improve stability. Tesamorelin specifically targets visceral adipose tissue reduction by stimulating lipolysis through GH-mediated pathways. It is the only FDA-approved treatment for HIV-associated lipodystrophy.
PT-141 (Bremelanotide / Vyleesi)
A synthetic cyclic heptapeptide melanocortin receptor agonist that activates MC3R and MC4R in the central nervous system. Unlike PDE5 inhibitors that act peripherally on vascular smooth muscle, PT-141 works centrally through hypothalamic melanocortin pathways that modulate sexual arousal and desire. It is a metabolite of Melanotan II without significant melanogenic activity.
Kisspeptin
A neuropeptide encoded by the KISS1 gene that serves as the master upstream regulator of the hypothalamic-pituitary-gonadal (HPG) axis. Kisspeptin activates GPR54 (KISS1R) on GnRH neurons, stimulating gonadotropin-releasing hormone secretion and subsequent LH and FSH release. It plays a critical role in puberty onset, reproductive function, and fertility regulation.
Oxytocin
A nine-amino acid cyclic neuropeptide produced in the hypothalamus and released from the posterior pituitary. Oxytocin mediates uterine contractions during labor, milk ejection during lactation, and social bonding behaviors. It modulates the HPA stress axis, reduces cortisol, and has anxiolytic properties. Intranasal administration reaches the CNS through olfactory and trigeminal nerve pathways.
GHRP-2
A synthetic hexapeptide growth hormone secretagogue that acts on the ghrelin receptor (GHS-R1a) in the hypothalamus and pituitary to stimulate growth hormone release. GHRP-2 is one of the most potent GH-releasing peptides, producing robust GH pulses while also increasing ACTH, cortisol, and prolactin to a modest degree. It amplifies the natural GH axis and works synergistically with GHRH analogs.
GHRP-6
A synthetic hexapeptide growth hormone secretagogue that stimulates the anterior pituitary via GHS-R1a receptor activation. GHRP-6 produces significant GH release and also potently stimulates appetite through ghrelin-mimetic activity in hypothalamic feeding centers. It increases gastric motility and has cytoprotective effects on gastric and cardiac tissue through NO-mediated pathways.
Hexarelin
A synthetic hexapeptide growth hormone secretagogue with the highest GH-releasing potency among GHRPs. Hexarelin binds both GHS-R1a and CD36 (scavenger receptor), giving it unique cardiovascular properties independent of GH release. It exhibits cardioprotective effects through reduced atherosclerotic plaque formation and improved cardiac contractility via direct myocardial receptor activation.
MK-677 (Ibutamoren)
An orally bioavailable, non-peptide growth hormone secretagogue that mimics the action of ghrelin at the GHS-R1a receptor. MK-677 stimulates sustained GH and IGF-1 elevation for up to 24 hours after a single oral dose without affecting cortisol levels. Its long duration of action and oral availability distinguish it from injectable GH secretagogues, and it preserves the pulsatile pattern of GH release.
Macimorelin (Macrilen)
An orally bioavailable growth hormone secretagogue approved as a diagnostic agent for adult growth hormone deficiency (AGHD). Macimorelin stimulates GH release via GHS-R1a agonism, and the GH response to a standardized oral dose is used to confirm or exclude AGHD. It offers a simpler, better-tolerated alternative to the insulin tolerance test and GHRH-arginine test for GH deficiency diagnosis.
Cosyntropin (Cortrosyn)
A synthetic peptide consisting of the first 24 amino acids of the 39-amino acid adrenocorticotropic hormone (ACTH). Cosyntropin retains full biological activity of native ACTH for stimulating adrenal cortisol production and is used as a diagnostic agent in the ACTH stimulation test to evaluate adrenal gland function. It binds to the MC2R receptor on adrenocortical cells, activating steroidogenesis.
Gonadorelin (GnRH)
A synthetic decapeptide identical to endogenous gonadotropin-releasing hormone. Gonadorelin stimulates the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary when administered in a pulsatile fashion. Continuous or high-dose administration paradoxically downregulates GnRH receptors, suppressing gonadotropin secretion, a principle exploited by GnRH agonist therapeutics.
Leuprolide (Lupron)
A synthetic nonapeptide GnRH agonist approximately 15-fold more potent than native GnRH. After an initial stimulatory phase (flare effect) lasting 1-2 weeks, chronic leuprolide administration downregulates pituitary GnRH receptors, resulting in profound suppression of LH, FSH, and downstream sex steroids. This chemical castration effect is exploited in treating hormone-sensitive cancers, endometriosis, and precocious puberty.
Goserelin (Zoladex)
A synthetic decapeptide GnRH agonist administered as a biodegradable subcutaneous implant that provides sustained drug release over 1 or 3 months. Like other GnRH agonists, goserelin initially stimulates and then suppresses the HPG axis, reducing sex hormone production to castrate or postmenopausal levels. The implant formulation eliminates the need for repeated injections and ensures compliance.
Cetrorelix (Cetrotide)
A synthetic decapeptide GnRH antagonist that competitively blocks pituitary GnRH receptors, producing immediate and dose-dependent suppression of LH and FSH without the initial flare effect seen with GnRH agonists. Cetrorelix prevents premature LH surges during controlled ovarian stimulation in IVF, allowing precise timing of oocyte maturation and retrieval.
Ganirelix
A synthetic decapeptide GnRH antagonist that competitively and reversibly blocks GnRH receptors on pituitary gonadotroph cells. Ganirelix rapidly suppresses LH secretion within hours of administration, preventing premature ovulation during assisted reproductive technology (ART) cycles. Its mechanism provides immediate suppression without the flare phase associated with GnRH agonists.
Carbetocin
A long-acting synthetic analog of oxytocin with a modified disulfide bridge that confers resistance to enzymatic degradation. Carbetocin has a half-life of approximately 40 minutes compared to 3-5 minutes for oxytocin, providing sustained uterotonic activity after a single injection. It selectively binds oxytocin receptors in the myometrium, promoting uterine contraction and reducing postpartum blood loss.
Atosiban
A competitive oxytocin/vasopressin V1a receptor antagonist used as a tocolytic agent to delay preterm labor. Atosiban blocks oxytocin-mediated myometrial contractions without the cardiovascular side effects associated with beta-adrenergic tocolytics. The peptide is administered as an initial bolus followed by a step-down infusion protocol over up to 48 hours.
Semax
A synthetic heptapeptide analog of the ACTH(4-7) fragment (Met-Glu-His-Phe-Pro-Gly-Pro) with nootropic and neuroprotective properties. Semax modulates BDNF and NGF expression, enhances monoaminergic neurotransmission, and provides neuroprotection through anti-oxidant and anti-inflammatory mechanisms. It crosses the blood-brain barrier via intranasal administration.
Selank
A synthetic analog of the endogenous tetrapeptide tuftsin (Thr-Lys-Pro-Arg) with an added Pro-Gly-Pro sequence for stability. Selank exhibits anxiolytic activity comparable to benzodiazepines without sedation, dependence, or withdrawal effects. It modulates the expression of BDNF, serotonin, dopamine, and norepinephrine, and influences IL-6 and GABA receptor expression.
Cerebrolysin
A porcine brain-derived peptide preparation consisting of low-molecular-weight neuropeptides and free amino acids that mimic the action of endogenous neurotrophic factors. Cerebrolysin exhibits neurotrophic activity similar to BDNF, GDNF, and CNTF, promoting neuronal survival, synaptic plasticity, and neurogenesis. It modulates GSK-3beta, CDK5, and calcineurin-NFAT signaling cascades involved in neurodegeneration.
P21 (Peptide)
A small synthetic peptide derived from the active region of ciliary neurotrophic factor (CNTF) designed to promote neurogenesis and synaptic plasticity. P21 is a tetrapeptide that crosses the blood-brain barrier and enhances dentate gyrus neurogenesis by increasing BDNF expression. Unlike full-length CNTF, P21 does not activate the JAK-STAT pathway or produce the anorectic and immunogenic effects of the parent protein.
Epithalon (Epitalon)
A synthetic tetrapeptide (Ala-Glu-Asp-Gly) based on the natural epithalamin peptide produced by the pineal gland. Epithalon activates telomerase, the enzyme responsible for maintaining telomere length, thereby potentially extending cellular replicative capacity. It also stimulates melatonin production and modulates neuroendocrine system function associated with aging.
MOTS-c
A mitochondrial-derived peptide encoded by the 12S rRNA gene of mitochondrial DNA. MOTS-c is a 16-amino acid peptide that acts as an exercise mimetic by activating AMPK and regulating metabolic homeostasis. It translocates to the nucleus under metabolic stress to regulate nuclear gene expression related to glucose metabolism and cellular stress responses.
Humanin
A 24-amino acid mitochondrial-derived peptide encoded within the 16S rRNA region of mitochondrial DNA. Humanin exerts cytoprotective and neuroprotective effects by interacting with IGFBP-3, BAX, and the FPRL-1 receptor. It inhibits apoptosis through suppression of the intrinsic mitochondrial death pathway and reduces amyloid-beta-induced neurotoxicity.
NAD+ Precursors (NMN)
Nicotinamide mononucleotide (NMN) is a direct biosynthetic precursor to nicotinamide adenine dinucleotide (NAD+), a coenzyme essential for cellular metabolism, DNA repair (via sirtuins and PARPs), and circadian rhythm regulation. NAD+ levels decline with age, and NMN supplementation restores tissue NAD+ levels, activating SIRT1-mediated pathways that regulate mitochondrial biogenesis and oxidative stress resistance.
SS-31 (Elamipretide)
A mitochondria-targeted tetrapeptide (D-Arg-dimethylTyr-Lys-Phe-NH2) that selectively concentrates in the inner mitochondrial membrane by binding to cardiolipin. SS-31 stabilizes cytochrome c interactions with cardiolipin, optimizing electron transport chain efficiency and reducing mitochondrial reactive oxygen species (ROS) production. It restores mitochondrial bioenergetics in aged and diseased tissues without acting as a conventional antioxidant scavenger.
FOXO4-DRI
A D-retro-inverso peptide designed to disrupt the interaction between FOXO4 and p53 in senescent cells. In senescent cells, FOXO4 sequesters p53 away from mitochondria, preventing p53-mediated apoptosis and enabling senescent cell survival. FOXO4-DRI competitively binds p53, releasing it to trigger selective apoptosis of senescent cells while sparing healthy cells, functioning as a senolytic agent.
Thymalin
A peptide bioregulator originally extracted from bovine thymus gland, consisting of a mixture of polypeptides that modulate immune function. Thymalin restores T-cell mediated immunity by promoting T-lymphocyte maturation and differentiation in the thymus. It also normalizes the ratio of T-helper to T-suppressor cells and enhances phagocytic activity of neutrophils and macrophages.
LL-37
The only human cathelicidin antimicrobial peptide, a 37-amino acid cationic peptide cleaved from the precursor protein hCAP18. LL-37 disrupts microbial membranes through electrostatic interactions and exerts broad-spectrum activity against bacteria, fungi, and enveloped viruses. Beyond direct antimicrobial effects, it modulates innate immunity by recruiting immune cells, promoting angiogenesis, and regulating inflammatory cytokine release.
VIP (Vasoactive Intestinal Peptide)
A 28-amino acid neuropeptide widely distributed in the central and peripheral nervous systems and immune cells. VIP acts through VPAC1 and VPAC2 receptors to produce potent anti-inflammatory effects by inhibiting the production of pro-inflammatory cytokines (TNF-alpha, IL-6, IL-12) and promoting regulatory T-cell differentiation. It also functions as a vasodilator, bronchodilator, and neuromodulator.
Thymosin Alpha 1 (Zadaxin)
A 28-amino acid peptide originally isolated from thymic tissue (thymosin fraction 5) that serves as a potent immunomodulator. Thymosin alpha 1 enhances T-cell maturation, dendritic cell function, and antibody responses by activating Toll-like receptors (TLR2, TLR9) on innate immune cells. It promotes Th1 immune responses and augments vaccine efficacy while modulating inflammatory cytokine production.
Thymopentin (TP-5)
A synthetic pentapeptide (Arg-Lys-Asp-Val-Tyr) corresponding to residues 32-36 of thymopoietin, a thymic hormone involved in T-cell differentiation. Thymopentin stimulates early T-cell precursor differentiation and modulates mature T-cell function by enhancing IL-2 production and expression of T-cell surface markers. It partially restores immune function in immunocompromised states without the risks of whole thymic extracts.
Thymulin
A zinc-containing nonapeptide (facteur thymique serique) produced exclusively by thymic epithelial cells. Thymulin requires zinc for biological activity and promotes T-lymphocyte differentiation, maturation, and function. Circulating thymulin levels decline progressively with age in parallel with thymic involution, and zinc deficiency independently impairs thymulin activity, linking nutritional status to immune competence.
KPV
A C-terminal tripeptide fragment (Lys-Pro-Val) of alpha-melanocyte-stimulating hormone (alpha-MSH) that retains potent anti-inflammatory activity without melanogenic effects. KPV inhibits NF-kB nuclear translocation and reduces production of pro-inflammatory cytokines including TNF-alpha, IL-1beta, and IL-6. It penetrates cell membranes and directly interacts with inflammatory signaling cascades, making it effective topically and orally for mucosal inflammation.
Enfuvirtide (Fuzeon)
A 36-amino acid synthetic peptide that inhibits HIV-1 entry into CD4+ T-cells by blocking the gp41-mediated membrane fusion step. Enfuvirtide binds to the first heptad repeat (HR1) region of gp41, preventing the conformational change required for viral-cell membrane fusion. It is the first and only FDA-approved fusion inhibitor and is active against HIV-1 strains resistant to other antiretroviral drug classes.
Melanotan II
A synthetic cyclic analog of alpha-melanocyte stimulating hormone (alpha-MSH) that non-selectively activates melanocortin receptors MC1R through MC5R. Melanotan II stimulates melanogenesis for skin tanning via MC1R, modulates sexual arousal through MC3R/MC4R in the hypothalamus, and reduces appetite through central MC4R activation. It is not FDA-approved and carries significant safety concerns.
Teriparatide (Forteo)
A recombinant form of the first 34 amino acids of human parathyroid hormone (PTH 1-34). When administered intermittently via daily subcutaneous injection, teriparatide stimulates osteoblastic bone formation more than osteoclastic resorption, producing a net anabolic effect on bone. It activates the PTH1 receptor on osteoblasts, increasing Wnt signaling, osteoblast differentiation, and survival while reducing sclerostin expression.
Abaloparatide (Tymlos)
A synthetic 34-amino acid peptide analog of parathyroid hormone-related protein (PTHrP 1-34) that selectively activates the RG conformation of the PTH1 receptor. This receptor selectivity produces a more transient signaling response compared to teriparatide, favoring anabolic bone formation with less stimulation of bone resorption and calcium mobilization. Abaloparatide increases bone mineral density at both cortical and trabecular sites.
Calcitonin
A 32-amino acid peptide hormone naturally produced by parafollicular C-cells of the thyroid gland. Calcitonin inhibits osteoclast-mediated bone resorption by binding to calcitonin receptors on osteoclasts, reducing their activity and number. Salmon calcitonin is approximately 40-50 times more potent than human calcitonin and has a longer half-life, making it the preferred therapeutic form.
Vosoritide (Voxzogo)
A C-type natriuretic peptide (CNP) analog that acts as an agonist at the natriuretic peptide receptor B (NPR-B) on growth plate chondrocytes. Vosoritide counteracts the constitutively activated FGFR3 signaling that suppresses endochondral ossification in achondroplasia. By stimulating the NPR-B/cGMP/MAPK pathway, it antagonizes the growth-inhibitory FGFR3 signal and restores more normal linear bone growth.
Vasopressin (ADH)
A nine-amino acid cyclic peptide hormone (arginine vasopressin) produced in the hypothalamus and released from the posterior pituitary. Vasopressin acts on V1a receptors (vascular smooth muscle vasoconstriction), V1b receptors (ACTH release from pituitary), and V2 receptors (aquaporin-2 insertion in renal collecting ducts for water reabsorption). It is essential for body water homeostasis and hemodynamic stability.
Desmopressin (DDAVP)
A synthetic analog of vasopressin with enhanced V2 receptor selectivity and minimal V1a vasopressor activity. Desmopressin has a deaminated cysteine at position 1 and D-arginine at position 8, increasing its antidiuretic potency 10-fold while largely eliminating the hypertensive effects of native vasopressin. Its prolonged half-life of 2-4 hours (vs. 10-20 minutes for vasopressin) allows convenient dosing for chronic conditions.
Terlipressin
A synthetic vasopressin analog and prodrug that is cleaved by endopeptidases to release lysine-vasopressin. Terlipressin has greater V1a receptor selectivity than vasopressin, producing splanchnic vasoconstriction that reduces portal pressure and redistributes blood flow to the kidneys. This mechanism addresses the pathophysiology of hepatorenal syndrome (HRS) by counteracting the splanchnic vasodilation that drives renal hypoperfusion.
Eptifibatide (Integrilin)
A synthetic cyclic heptapeptide modeled after the KGD (Lys-Gly-Asp) disintegrin sequence found in the venom of the southeastern pygmy rattlesnake (Sistrurus miliarius barbouri). Eptifibatide is a potent, reversible glycoprotein IIb/IIIa receptor antagonist that blocks the final common pathway of platelet aggregation by preventing fibrinogen and von Willebrand factor binding to activated platelets.
Nesiritide (Natrecor)
A recombinant form of human B-type natriuretic peptide (BNP), a 32-amino acid peptide naturally produced by ventricular cardiomyocytes in response to volume overload and wall stress. Nesiritide binds natriuretic peptide receptor A (NPR-A), activating guanylyl cyclase and increasing intracellular cGMP to produce venous, arterial, and coronary vasodilation, natriuresis, and suppression of the renin-angiotensin-aldosterone and sympathetic nervous systems.
Angiotensin II (Giapreza)
A synthetic form of the endogenous octapeptide angiotensin II, the primary effector of the renin-angiotensin system. Angiotensin II acts on AT1 receptors on vascular smooth muscle to produce potent vasoconstriction, and on the adrenal cortex to stimulate aldosterone release. Exogenous administration raises blood pressure in vasodilatory shock refractory to conventional vasopressors by restoring vascular tone through a mechanism complementary to catecholamine vasopressors.
Bivalirudin (Angiomax)
A synthetic 20-amino acid peptide that acts as a direct thrombin inhibitor by binding both the catalytic active site and anion-binding exosite 1 of thrombin. Bivalirudin inhibits both free and clot-bound thrombin, providing more predictable anticoagulation than heparin without requiring antithrombin III as a cofactor. It is enzymatically cleaved by thrombin itself, producing a self-limiting anticoagulant effect with a 25-minute half-life.
Romiplostim (Nplate)
A thrombopoietin (TPO) receptor agonist consisting of a peptide sequence that binds the TPO receptor (c-Mpl) fused to an IgG1 Fc domain (peptibody). Romiplostim activates JAK2/STAT5 signaling in megakaryocyte progenitors, promoting megakaryocyte proliferation, differentiation, and platelet production. It has no sequence homology to endogenous TPO, minimizing the risk of cross-reactive antibody formation.
Pegcetacoplan (Empaveli)
A pegylated cyclic peptide that inhibits complement component C3, the central node of all three complement activation pathways (classical, lectin, and alternative). By binding C3 and preventing its cleavage into C3a and C3b, pegcetacoplan blocks both intravascular hemolysis (mediated by membrane attack complex) and extravascular hemolysis (mediated by C3b opsonization and phagocytosis). This dual mechanism addresses the limitation of C5 inhibitors that only prevent intravascular hemolysis.
Carfilzomib (Kyprolis)
A tetrapeptide epoxyketone proteasome inhibitor that irreversibly binds the chymotrypsin-like (beta5) subunit of the 20S proteasome. By blocking proteasomal degradation of ubiquitinated proteins, carfilzomib causes accumulation of misfolded proteins, endoplasmic reticulum stress, and activation of the unfolded protein response, leading to apoptosis preferentially in malignant plasma cells. Its irreversible binding confers greater proteasome inhibition than bortezomib.
Bortezomib (Velcade)
A modified dipeptidyl boronic acid that reversibly inhibits the chymotrypsin-like activity of the 26S proteasome. Bortezomib disrupts the ubiquitin-proteasome pathway, stabilizing pro-apoptotic factors and inhibiting NF-kB activation, which is constitutively active in many hematologic malignancies. It was the first proteasome inhibitor approved for cancer treatment and fundamentally changed the treatment landscape of multiple myeloma.
Lutetium-177 dotatate (Lutathera)
A radiolabeled somatostatin analog consisting of the peptide DOTA-Tyr3-octreotate chelated to the beta-emitting radioisotope lutetium-177. Lutathera binds with high affinity to somatostatin receptor subtype 2 (SSTR2), which is overexpressed on neuroendocrine tumor cells, delivering targeted radiation therapy directly to tumor cells while sparing surrounding normal tissue. This peptide receptor radionuclide therapy (PRRT) approach combines receptor-targeted delivery with cytotoxic radiation.
Leuprolide (Lupron) - Oncology
A GnRH agonist used in oncology for androgen deprivation therapy (ADT) in prostate cancer and hormone suppression in premenopausal breast cancer. Chronic administration produces sustained downregulation of pituitary GnRH receptors, achieving medical castration with testosterone levels below 50 ng/dL. The initial testosterone flare can be mitigated by co-administration of an antiandrogen. Depot formulations provide sustained release for up to 6 months.
Octreotide (Sandostatin)
A synthetic octapeptide analog of somatostatin with a substantially longer half-life (90 minutes IV, 6 hours subcutaneous vs. 2 minutes for native somatostatin). Octreotide binds somatostatin receptors (primarily SSTR2 and SSTR5) to inhibit the secretion of GH, glucagon, insulin, gastrin, secretin, VIP, and other GI hormones. It reduces splanchnic blood flow, GI motility, and exocrine pancreatic secretion.
Lanreotide (Somatuline Depot)
A synthetic octapeptide analog of somatostatin with high affinity for SSTR2 and moderate affinity for SSTR5 receptors. Lanreotide is formulated as a supersaturated solution that forms a drug depot at the injection site, providing sustained release over 4 weeks. It inhibits GH secretion, GI hormone release, and has direct antiproliferative effects on neuroendocrine tumor cells through cell cycle arrest and apoptosis induction.
Pasireotide (Signifor)
A multireceptor-targeted somatostatin analog with high binding affinity for SSTR1, SSTR2, SSTR3, and SSTR5, particularly notable for its 40-fold greater affinity for SSTR5 compared to octreotide. This receptor profile makes pasireotide uniquely effective in Cushing's disease, where corticotroph adenomas predominantly express SSTR5. Pasireotide suppresses ACTH secretion from pituitary corticotroph tumors, reducing cortisol production.
Plecanatide (Trulance)
A synthetic 16-amino acid peptide structurally related to uroguanylin, an endogenous intestinal peptide that regulates fluid and electrolyte homeostasis in the GI tract. Plecanatide activates guanylate cyclase-C (GC-C) receptors on intestinal epithelial cells in a pH-dependent manner, preferentially in the proximal small intestine where pH is slightly acidic. GC-C activation increases intracellular and extracellular cGMP, stimulating chloride and bicarbonate secretion while reducing visceral pain signaling.
Linaclotide (Linzess)
A synthetic 14-amino acid peptide structurally related to the heat-stable enterotoxin of Escherichia coli and the endogenous peptide guanylin. Linaclotide activates guanylate cyclase-C (GC-C) on the luminal surface of intestinal epithelium, increasing intracellular cGMP to stimulate CFTR-mediated chloride and bicarbonate secretion, accelerating intestinal transit. Extracellular cGMP also reduces firing of visceral afferent pain fibers, providing analgesic effects in the gut.
Secretin
A 27-amino acid peptide hormone produced by S-cells of the duodenal and jejunal mucosa in response to acidic chyme entering the small intestine. Secretin stimulates pancreatic ductal cells to secrete bicarbonate-rich fluid, neutralizing duodenal acid, and promotes bile flow from hepatocytes. It was the first hormone ever identified (Bayliss and Starling, 1902) and serves as a key diagnostic tool in gastroenterology and endocrinology.
Larazotide
A synthetic octapeptide derived from Vibrio cholerae zonula occludens toxin that acts as a tight junction regulator. Larazotide acetate modulates intestinal permeability by preventing zonulin-mediated opening of tight junctions between enterocytes. By reducing paracellular permeability, it aims to prevent gluten peptide translocation across the intestinal barrier in celiac disease, reducing the immune-mediated inflammatory response triggered by gluten exposure.
Ziconotide (Prialt)
A synthetic 25-amino acid peptide identical to omega-conotoxin MVIIA, a neurotoxin found in the venom of the marine cone snail Conus magus. Ziconotide selectively and reversibly blocks N-type voltage-gated calcium channels (Cav2.2) in the dorsal horn of the spinal cord, inhibiting neurotransmitter release from primary afferent nociceptive neurons. It provides analgesia without opioid receptor activation, tolerance development, or respiratory depression.
Difelikefalin (Korsuva)
A selective kappa-opioid receptor (KOR) agonist peptide that does not cross the blood-brain barrier, providing peripheral analgesia and anti-pruritic effects without central opioid side effects such as euphoria, dysphoria, sedation, or addiction. Difelikefalin activates kappa receptors on peripheral sensory neurons and immune cells to reduce itch signaling and inflammation. Its restricted CNS penetration is a deliberate design feature to avoid abuse potential.
ARA-290
A synthetic 11-amino acid peptide derived from the structure of erythropoietin (EPO) that selectively activates the innate repair receptor (IRR), a heteromer of the EPO receptor and the beta common receptor (CD131). Unlike EPO, ARA-290 does not stimulate erythropoiesis or promote thrombosis. It produces cytoprotective, anti-inflammatory, and tissue-reparative effects by activating the IRR on neurons, immune cells, and endothelial cells.
Afamelanotide (Scenesse)
A synthetic 13-amino acid analog of alpha-melanocyte-stimulating hormone (alpha-MSH) with a substitution of norleucine at position 4 that confers enhanced potency and enzymatic stability. Afamelanotide activates melanocortin-1 receptors (MC1R) on melanocytes, stimulating eumelanin production independent of UV exposure. The resulting increase in skin eumelanin provides photoprotection by absorbing UV radiation and scavenging reactive oxygen species.
Pentagastrin
A synthetic pentapeptide containing the C-terminal tetrapeptide sequence of gastrin (Trp-Met-Asp-Phe-NH2) linked to beta-alanine. Pentagastrin stimulates gastric acid secretion by binding to cholecystokinin-2 (CCK2) receptors on parietal cells, and stimulates calcitonin release from thyroid C-cells. It has been used as a diagnostic agent for both gastric acid secretory capacity testing and provocative testing for medullary thyroid carcinoma (MTC).
Icatibant (Firazyr)
A synthetic decapeptide bradykinin B2 receptor antagonist containing five non-natural amino acids for enhanced stability and receptor selectivity. Icatibant competitively blocks bradykinin, the primary mediator of swelling in hereditary angioedema (HAE) caused by C1 esterase inhibitor deficiency. By preventing bradykinin-induced vasodilation and increased vascular permeability, it rapidly reverses mucosal and subcutaneous edema.
Palmitoylethanolamide (PEA)
An endogenous fatty acid amide belonging to the N-acylethanolamine family, naturally produced by cells in response to tissue damage and inflammation. PEA acts primarily through peroxisome proliferator-activated receptor alpha (PPAR-alpha), downregulating mast cell activation and pro-inflammatory mediator release. It also modulates the endocannabinoid system via the entourage effect, enhancing anandamide activity at CB1/CB2 receptors and TRPV1 channels without directly binding cannabinoid receptors.
Orforglipron
Orforglipron is a non-peptide, oral small-molecule glucagon-like peptide-1 receptor (GLP-1R) agonist designed to overcome the need for injectable delivery. It activates the GLP-1 receptor to enhance glucose-dependent insulin secretion, suppress glucagon release, and slow gastric emptying. The therapeutic rationale centers on improving adherence in type 2 diabetes and obesity management by providing once-daily oral dosing as an alternative to injectable GLP-1 receptor agonists.
Mazdutide
Mazdutide is a dual glucagon-like peptide-1 (GLP-1) and glucagon receptor agonist delivered as a synthetic peptide. By co-activating both receptors, it aims to combine the glucose-lowering and weight-reducing effects of GLP-1 with the energy-expenditure and hepatic fat-reducing actions of glucagon receptor stimulation. This dual mechanism is hypothesized to provide enhanced metabolic benefits in obesity and metabolic dysfunction-associated steatotic liver disease.
Survodutide
Survodutide is a dual agonist targeting both the glucagon-like peptide-1 (GLP-1) and glucagon receptors, formulated as a peptide for subcutaneous administration. The compound is designed to leverage GLP-1-mediated glucose control and appetite suppression alongside glucagon-driven increases in energy expenditure and reduction of hepatic steatosis. It is being investigated for type 2 diabetes, obesity, and metabolic dysfunction-associated steatohepatitis.
CagriSema
CagriSema is a fixed-ratio combination of cagrilintide, an amylin analog, and semaglutide, a GLP-1 receptor agonist, both delivered as peptides via subcutaneous injection. Cagrilintide acts on amylin receptors to reduce appetite and slow gastric emptying, while semaglutide enhances insulin secretion and suppresses glucagon. The combination is intended to achieve greater weight loss than either agent alone in the treatment of obesity.
Amycretin
Amycretin is a dual agonist targeting both the amylin and calcitonin receptors, designed as a peptide therapeutic for obesity. Amylin receptor activation reduces food intake and delays gastric emptying, while calcitonin receptor engagement may further contribute to appetite suppression and weight loss. The compound represents a novel approach distinct from GLP-1-based therapies.
Efinopegdutide
Efinopegdutide is a long-acting dual agonist of the GLP-1 and glucagon receptors, utilizing PEGylation to extend half-life and enable once-weekly dosing. The compound combines GLP-1-mediated glycemic control and appetite reduction with glucagon-driven energy expenditure and hepatic fat mobilization. It is under investigation for obesity and metabolic dysfunction-associated steatohepatitis.
Danuglipron
Danuglipron is an oral, non-peptide small-molecule agonist of the GLP-1 receptor developed to provide convenient daily dosing for type 2 diabetes and obesity. It mimics the effects of endogenous GLP-1 by enhancing glucose-dependent insulin secretion, suppressing glucagon, and slowing gastric emptying. The small-molecule structure enables oral bioavailability without the need for injection.
Ecnoglutide
Ecnoglutide is a long-acting GLP-1 receptor agonist peptide designed for once-weekly subcutaneous administration. It acts by enhancing glucose-dependent insulin secretion, reducing glucagon levels, and delaying gastric emptying to improve glycemic control and promote weight loss. The extended half-life is achieved through structural modifications that resist enzymatic degradation and renal clearance.
Cotadutide
Cotadutide is a dual agonist of the GLP-1 and glucagon receptors formulated as a peptide for subcutaneous injection. It is designed to harness GLP-1-mediated improvements in glucose homeostasis and satiety alongside glucagon receptor activation to enhance energy expenditure and reduce hepatic fat. Primary indications under investigation include obesity, type 2 diabetes, and metabolic dysfunction-associated steatohepatitis.
Glepaglutide
Glepaglutide is a long-acting GLP-2 receptor agonist peptide developed for the treatment of short bowel syndrome. GLP-2 promotes intestinal growth, enhances nutrient and fluid absorption, and reduces gastric secretion, thereby improving intestinal function in patients with compromised bowel length. The compound is administered subcutaneously to sustain therapeutic effects over extended intervals.
Apraglutide
Apraglutide is a long-acting glucagon-like peptide-2 (GLP-2) receptor agonist designed to promote intestinal growth and improve absorption in patients with short bowel syndrome. The peptide analogue shares structural homology with native GLP-2 but incorporates modifications that extend its half-life and enhance resistance to dipeptidyl peptidase-4 degradation. By binding to GLP-2 receptors in the intestinal epithelium, apraglutide stimulates crypt cell proliferation and reduces gastric emptying and secretion, supporting adaptive intestinal function.
Teduglutide (Gattex)
Teduglutide is a recombinant analogue of human glucagon-like peptide-2 (GLP-2) comprising 33 amino acids with a single amino acid substitution that confers resistance to enzymatic degradation by dipeptidyl peptidase-4. This GLP-2 receptor agonist enhances intestinal epithelial barrier function, promotes mucosal growth, and increases mesenteric blood flow, thereby improving nutrient and fluid absorption. The therapeutic rationale centers on reducing dependence on parenteral nutrition in patients with short bowel syndrome by augmenting remnant bowel adaptive capacity.
Beinaglutide
Beinaglutide is a recombinant glucagon-like peptide-1 (GLP-1) receptor agonist engineered with structural modifications to prolong plasma half-life and improve metabolic stability. The peptide activates GLP-1 receptors on pancreatic beta cells, stimulating glucose-dependent insulin secretion while suppressing glucagon release, delaying gastric emptying, and promoting satiety. Its mechanism targets multiple pathways involved in glycemic control, making it suitable for the treatment of type 2 diabetes mellitus.
Albiglutide (Tanzeum)
Albiglutide is a GLP-1 receptor agonist consisting of a tandem repeat of modified human GLP-1 sequences fused to human albumin, creating a protein of approximately 73 kilodaltons with extended pharmacokinetic properties. The albumin fusion technology allows for once-weekly dosing by delaying renal clearance and protecting the peptide from enzymatic degradation. By activating GLP-1 receptors, albiglutide enhances glucose-dependent insulin secretion and suppresses inappropriate glucagon release in patients with type 2 diabetes.
Taspoglutide
Taspoglutide is a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist derived from human GLP-1 with amino acid substitutions designed to resist dipeptidyl peptidase-4 degradation and extend duration of action. The peptide activates pancreatic GLP-1 receptors to promote glucose-dependent insulin secretion, inhibit glucagon release, and slow gastric emptying. Its structural modifications were intended to support once-weekly administration for the treatment of type 2 diabetes mellitus.
Pemvidutide
Pemvidutide is a dual receptor agonist targeting both glucagon-like peptide-1 (GLP-1) and glucagon receptors, designed to combine the insulinotropic and appetite-suppressing effects of GLP-1 with the energy expenditure and lipolytic actions of glucagon. This balanced co-agonist strategy aims to achieve superior weight loss and metabolic benefits compared to GLP-1 monotherapy while mitigating the hyperglycemic effects of isolated glucagon receptor activation. The peptide architecture incorporates amino acid modifications to optimize receptor binding affinity and pharmacokinetic duration.
Cagrilintide
Cagrilintide is a long-acting amylin analogue engineered with structural modifications to extend half-life and enable once-weekly dosing for the treatment of obesity and type 2 diabetes. Amylin is a 37-amino-acid neuroendocrine hormone co-secreted with insulin that reduces food intake by slowing gastric emptying, enhancing satiety, and modulating central appetite pathways. Cagrilintide selectively activates amylin receptors in the area postrema and other key brain regions involved in energy homeostasis.
Enlicitide
Enlicitide is an investigational peptide agonist designed to modulate metabolic pathways involved in energy balance and glucose homeostasis. Limited publicly available structural and mechanistic data suggest it may target incretin or related neuroendocrine pathways, though detailed receptor pharmacology has not been fully disclosed in the peer-reviewed literature. The compound is being explored for potential applications in obesity and metabolic disorders.
Capromorelin (Entyce)
Capromorelin is a selective ghrelin receptor agonist, or growth hormone secretagogue, that mimics the endogenous peptide hormone ghrelin by binding to the GHS-R1a receptor in the hypothalamus and pituitary. Activation of ghrelin receptors stimulates appetite, promotes growth hormone release, and modulates energy balance, providing a therapeutic rationale for conditions characterized by inappetence and weight loss. The compound is formulated as an oral solution, distinguishing it from injectable peptide therapies.
Anamorelin (Adlumiz)
Anamorelin is an orally active selective ghrelin receptor agonist designed to stimulate appetite and promote anabolic processes by mimicking endogenous ghrelin at the growth hormone secretagogue receptor (GHS-R1a). The small-molecule peptidomimetic increases growth hormone and IGF-1 secretion while enhancing food intake and lean body mass, targeting the muscle wasting and cachexia associated with chronic illness. Its oral bioavailability and receptor selectivity differentiate it from earlier injectable ghrelin analogues.
Relamorelin
Relamorelin is a synthetic pentapeptide ghrelin receptor agonist designed to stimulate growth hormone secretion and promote gastric motility. It binds selectively to the growth hormone secretagogue receptor type 1a (GHS-R1a), mimicking the action of endogenous ghrelin. The peptide was developed primarily for the treatment of diabetic gastroparesis and other disorders of gastric emptying, with potential applications in cachexia and functional dyspepsia.
Mod GRF 1-29 (CJC-1295 no DAC)
Modified GRF 1-29 is a synthetic analogue of growth hormone releasing hormone (GHRH) comprising 29 amino acids with four amino acid substitutions to enhance stability. These modifications increase resistance to enzymatic degradation compared to native GHRH while maintaining receptor affinity and biological activity. The compound stimulates pulsatile growth hormone release from the anterior pituitary without the half-life extension conferred by drug affinity complex technology.
Tabimorelin
Tabimorelin is an orally active synthetic ghrelin mimetic and selective GHS-R1a agonist developed to stimulate growth hormone release. Unlike peptide analogues, tabimorelin was designed as a small molecule with improved oral bioavailability and stability. The therapeutic rationale centered on treating frailty, functional decline in the elderly, and conditions associated with growth hormone deficiency.
Somatropin (Genotropin)
Somatropin is recombinant human growth hormone (rhGH) consisting of 191 amino acids identical in sequence to endogenous pituitary growth hormone. It binds to growth hormone receptors on target tissues to stimulate linear growth, protein synthesis, lipolysis, and carbohydrate metabolism. Genotropin is one of several branded formulations of somatropin approved for multiple indications including pediatric growth hormone deficiency, Turner syndrome, and adult growth hormone deficiency.
Somapacitan (Sogroya)
Somapacitan is a long-acting growth hormone analogue engineered by attaching an albumin-binding moiety to recombinant human growth hormone. This modification extends the half-life to allow once-weekly subcutaneous administration, compared to daily injections required for standard somatropin. The peptide retains growth hormone receptor agonist activity with pharmacokinetic enhancement intended to improve treatment adherence.
Lonapegsomatropin (Skytrofa)
Lonapegsomatropin is a long-acting prodrug of somatropin created through site-specific PEGylation that releases active growth hormone after administration. The PEG moiety extends circulating half-life and enables once-weekly dosing for pediatric growth hormone deficiency. This represents a transient modification strategy in which the PEG is cleaved to yield native growth hormone.
Pegvisomant (Somavert)
Pegvisomant is a PEGylated growth hormone receptor antagonist engineered from human growth hormone with nine amino acid substitutions that confer antagonist properties. The molecule binds to growth hormone receptors but does not activate downstream signaling, effectively blocking the action of endogenous growth hormone. It is used exclusively for the treatment of acromegaly in patients with inadequate response to surgery or other medical therapies.
Mecasermin (Increlex)
Mecasermin is recombinant human insulin-like growth factor 1 (IGF-1) consisting of 70 amino acids identical to the endogenous peptide hormone. It binds to IGF-1 receptors to promote growth and anabolic processes, bypassing the need for growth hormone receptor signaling. Mecasermin is indicated specifically for children with severe primary IGF-1 deficiency or growth hormone gene deletion who have developed neutralizing antibodies to growth hormone.
GHRH (Sermorelin 1-44)
Sermorelin is a synthetic 44-amino acid peptide corresponding to the biologically active portion of human growth hormone releasing hormone (GHRH). It stimulates endogenous growth hormone secretion from the anterior pituitary by binding to GHRH receptors. Originally approved for diagnostic testing of growth hormone secretion, sermorelin was subsequently marketed for treatment of growth hormone deficiency in children before being voluntarily withdrawn.
Ghrelin (Native)
Ghrelin is a naturally occurring 28-amino acid peptide hormone produced primarily in the stomach with an essential octanoyl modification at serine-3 required for biological activity. It functions as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a), stimulating growth hormone release, appetite, and gastric motility. Ghrelin plays a central role in energy homeostasis, feeding behavior, and metabolic regulation.
Obestatin
Obestatin is a 23-amino acid peptide hormone derived from post-translational processing of the ghrelin gene product preproghrelin. It was initially proposed to oppose ghrelin's orexigenic effects by binding to the GPR39 receptor and promoting satiety, though this mechanism remains controversial. The peptide has been investigated for potential roles in regulating food intake, gastrointestinal motility, and metabolic homeostasis.
GHRP-1
Growth Hormone Releasing Peptide-1 is a synthetic hexapeptide belonging to the growth hormone secretagogue family. It acts as a weak agonist at the ghrelin receptor (GHS-R1a) to stimulate pulsatile growth hormone release from the anterior pituitary. GHRP-1 has limited potency compared to later-generation secretagogues and served primarily as a prototype for subsequent drug development.
Pentadeca Arginate (PDA)
Pentadeca Arginate is a synthetic 15-arginine polypeptide designed to enhance cellular uptake and delivery of therapeutic molecules. The polyarginine structure confers cell-penetrating properties by interacting with negatively charged cell membrane components. It has been explored as a carrier for facilitating intracellular delivery of bioactive compounds and as a potential modulator of tissue repair processes.
Thymosin Beta-4 Fragment (TB4-Frag)
Thymosin Beta-4 Fragment refers to bioactive segments derived from the 43-amino acid thymosin beta-4 protein, most commonly a 7-amino acid N-terminal sequence (Ac-SDKP). These fragments retain specific biological activities of the parent peptide, including modulation of actin polymerization, angiogenesis, and inflammation. Shorter fragments may offer improved stability and targeted activity compared to full-length thymosin beta-4.
Cathelicidin LL-37 Fragments
Cathelicidin LL-37 fragments are truncated sequences derived from the human antimicrobial peptide LL-37, which is a 37-amino acid cleavage product of the cathelicidin precursor hCAP18. These fragments retain antimicrobial, immunomodulatory, and wound healing properties while potentially offering improved stability or reduced cytotoxicity. Specific fragments have been designed to preserve angiogenic and chemotactic activities relevant to tissue repair.
FGL Peptide
FGL peptide is a 15-amino acid synthetic sequence derived from the neural cell adhesion molecule (NCAM) that mimics the fibronectin-like domain. It promotes neurite outgrowth and synaptic plasticity by engaging NCAM and fibroblast growth factor receptors without requiring direct cell-cell adhesion. The peptide has been investigated for neuroprotective and cognitive-enhancing properties in models of neurological injury and disease.
GHK (Glycyl-Histidyl-Lysine)
GHK is a naturally occurring tripeptide with high affinity for copper ions, forming the GHK-Cu complex. It is present in human plasma, saliva, and urine at concentrations that decline with age. The peptide modulates extracellular matrix remodeling, metalloproteinase activity, and growth factor signaling, contributing to wound healing and tissue repair processes.
Matrikine Peptides
Matrikine peptides are bioactive fragments released from extracellular matrix proteins during tissue remodeling or injury. These sequences, derived from collagen, elastin, fibronectin, and laminin, regulate cellular processes including migration, proliferation, and differentiation by binding to cell surface receptors. Matrikines serve as endogenous signals coordinating wound healing and tissue homeostasis.
AHK-Cu (Copper Tripeptide-3)
AHK-Cu is a synthetic copper-binding tripeptide consisting of alanine-histidine-lysine complexed with copper ions. It shares structural and functional similarities with GHK-Cu but contains alanine in place of glycine at the N-terminus. The peptide is proposed to promote collagen production, angiogenesis, and antioxidant defenses in skin and other tissues.
Body Protection Compound (BPC) Variants
BPC variants are synthetic peptide sequences related to a pentadecapeptide derived from human gastric juice, commonly designated BPC-157. These peptides are proposed to exhibit gastroprotective, angiogenic, and tissue repair properties through mechanisms that may involve nitric oxide pathways, growth factor modulation, and VEGF receptor interactions. The exact structure-activity relationships and receptor targets remain incompletely defined.
Collagen Tripeptide F (CTP-F)
Collagen Tripeptide F is a synthetic tripeptide designed to mimic fragments of native collagen that appear during tissue remodeling. It is hypothesized to bind to fibroblast surface receptors and promote extracellular matrix deposition, thereby accelerating wound healing and connective tissue repair. The tripeptide structure is intended to enhance bioavailability compared to larger collagen molecules.
Sinapultide (KL4 Surfactant)
Sinapultide is a synthetic 21-amino acid peptide that mimics the structure and function of surfactant protein B, a critical component of pulmonary surfactant. When combined with phospholipids, sinapultide forms a surface-active complex that reduces alveolar surface tension, improving gas exchange and lung compliance. It has been investigated primarily for treatment of acute respiratory distress syndrome and neonatal respiratory distress.
Chrysalin (TP508)
Chrysalin, also known as TP508, is a 23-amino acid synthetic peptide derived from the receptor-binding domain of human thrombin. It is designed to activate non-proteolytic thrombin receptors on endothelial cells, fibroblasts, and osteoblasts, thereby promoting angiogenesis, granulation tissue formation, and bone repair. The peptide retains thrombin's tissue repair signaling properties without procoagulant activity.
Nexagon (Gap Junction Peptide)
Nexagon is a synthetic peptide designed to transiently modulate gap junction intercellular communication by mimicking a segment of the connexin protein family. The mechanism involves temporary inhibition of connexin43-mediated channels during the early inflammatory phase of wound healing, which may reduce inflammatory cell infiltration and subsequent scar formation. This approach aims to shift the healing process toward regeneration rather than fibrosis.
OP-1 / BMP-7
OP-1, or osteogenic protein-1, is the recombinant form of bone morphogenetic protein-7 (BMP-7), a member of the transforming growth factor-beta superfamily. This homodimeric protein induces differentiation of mesenchymal stem cells into osteoblasts and chondrocytes, stimulating new bone formation. It was developed primarily for spinal fusion procedures and long bone non-unions where autologous bone graft is not feasible.
Dalargin
Dalargin is a synthetic hexapeptide analog of leucine-enkephalin with enhanced metabolic stability due to D-amino acid substitutions. It acts as a selective delta opioid receptor agonist with peripheral and central effects, including modulation of stress responses, anti-inflammatory activity, and cytoprotection in gastrointestinal and vascular tissues. Unlike classical opioids, dalargin exhibits reduced central analgesic potency but pronounced tissue-protective properties.
Dihexa
Dihexa is a small synthetic hexapeptide derived from angiotensin IV, designed to bind and potentiate hepatocyte growth factor (HGF) signaling through the c-Met receptor. This action is hypothesized to promote synaptogenesis, dendritic spine formation, and neuronal survival in models of cognitive impairment. Dihexa exhibits high oral bioavailability and blood-brain barrier penetration due to its small size and lipophilic character.
NAP (Davunetide)
NAP, also known as davunetide, is an eight-amino acid peptide derived from activity-dependent neuroprotective protein (ADNP). It is thought to stabilize microtubules by interacting with tubulin and promoting cytoskeletal integrity, thereby protecting neurons from oxidative stress, excitotoxicity, and tauopathies. Intranasal delivery was pursued to achieve direct central nervous system access while minimizing systemic exposure.
Nemifitide
Nemifitide is a synthetic pentapeptide analog of the endogenous neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH). It acts on melanocortin receptors, particularly MC4, to modulate inflammatory pathways, oxidative stress, and neuronal excitability. The peptide has been investigated for neuroprotection in settings of acute brain injury and neurodegenerative disease.
Intranasal Insulin
Intranasal insulin involves the administration of regular human insulin via nasal spray to target central nervous system insulin receptors without causing systemic hypoglycemia. Insulin signaling in the brain is implicated in synaptic plasticity, glucose metabolism, and amyloid clearance, providing a rationale for cognitive enhancement in insulin-resistant states and Alzheimer disease. Intranasal delivery bypasses the blood-brain barrier via olfactory and trigeminal nerve pathways.
Spadin
Spadin is a 17-amino acid peptide derived from the propeptide released during maturation of sortilin, a neurotensin receptor. It functions as an antagonist of the TREK-1 potassium channel, which is implicated in the pathophysiology of major depressive disorder. By blocking TREK-1, spadin increases neuronal excitability and promotes hippocampal neurogenesis, providing a novel antidepressant mechanism distinct from monoaminergic pathways.
Cortexin
Cortexin is a complex polypeptide mixture extracted from bovine cerebral cortex, containing a range of neuropeptides and neurotrophic factors with combined molecular weights below 10 kDa. The preparation is proposed to exert neurotrophic and neuroprotective effects by modulating glutamatergic transmission, reducing oxidative stress, and supporting synaptic function. It has been used primarily in Russia and Eastern Europe for cognitive and neurological indications.
Pinealon
Pinealon is a synthetic tripeptide (Glu-Asp-Arg) developed as part of the Khavinson peptide bioregulator series, designed to mimic endogenous short peptides that regulate gene expression in neural tissues. It is hypothesized to interact with chromatin and influence transcription of genes involved in neuronal survival and plasticity. Pinealon has been studied primarily in the context of age-related cognitive decline and neurodegenerative models.
N-acetyl Semax Amidate
N-acetyl Semax Amidate is a modified heptapeptide derivative of adrenocorticotropic hormone (ACTH) fragments, engineered with N-terminal acetylation and C-terminal amidation to enhance metabolic stability and blood-brain barrier penetration. It is believed to modulate brain-derived neurotrophic factor (BDNF) expression, enhance dopaminergic and serotonergic signaling, and improve cognitive performance and stress resilience. This analog exhibits prolonged activity compared to the parent Semax peptide.
N-acetyl Selank Amidate
N-acetyl Selank Amidate is a synthetic heptapeptide analog of the immunomodulatory peptide tuftsin, modified with acetylation and amidation to increase half-life and central nervous system activity. It is reported to exert anxiolytic and nootropic effects through modulation of enkephalin metabolism and influencing monoamine neurotransmitter systems without sedation or dependency. The peptide has been explored for anxiety, cognitive enhancement, and stress adaptation.
Bromantane-adjacent Peptides
Bromantane-adjacent peptides refer to a theoretical class of compounds that may share structural or functional motifs with bromantane, a synthetic adaptogen that influences dopamine synthesis and has mild psychostimulant properties. While bromantane itself is not a peptide, peptide analogs designed to mimic its dopaminergic or anti-asthenic effects are an area of early exploration. Such peptides would aim to enhance cognitive performance and reduce fatigue through modulation of catecholamine pathways.
ACTH (4-10) Analogs
ACTH (4-10) analogs are synthetic peptides derived from the 4 to 10 amino acid sequence of adrenocorticotropic hormone, engineered to preserve neurotrophic and cognitive-enhancing properties while eliminating steroidogenic activity. These fragments are thought to influence attention, memory consolidation, and synaptic plasticity through melanocortin receptor interactions and modulation of neurotransmitter systems. They represent a class of nootropic peptides explored since the 1970s.
Orexin A
Orexin A is a 33-amino acid neuropeptide produced in the lateral hypothalamus that plays a critical role in the regulation of wakefulness, arousal, and energy homeostasis. It binds with high affinity to both orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R), promoting cortical activation and stabilizing the wake state. Deficiency of orexin signaling is the hallmark of narcolepsy type 1, making orexin replacement a rational therapeutic strategy.
Orexin B
Orexin B is a 28-amino acid neuropeptide closely related to orexin A, also synthesized in hypothalamic neurons and involved in promoting wakefulness and regulating feeding behavior. It exhibits preferential binding to orexin receptor 2 (OX2R) compared to OX1R. Orexin B contributes to the maintenance of arousal and the integration of metabolic and circadian signals.
Neurotensin
Neurotensin is a 13-amino acid neuropeptide widely distributed in the central nervous system and gastrointestinal tract, where it modulates dopaminergic neurotransmission, nociception, and intestinal function. It acts primarily through the neurotensin receptor 1 (NTSR1), influencing mesolimbic and nigrostriatal pathways implicated in motivation, reward, and motor control. Neurotensin has been studied for its potential roles in schizophrenia, pain modulation, and cognitive function.
Galanin
Galanin is a 29 or 30 amino acid neuropeptide widely distributed throughout the central and peripheral nervous systems. It acts through three G protein-coupled receptor subtypes (GAL1, GAL2, and GAL3) to modulate neurotransmission, particularly in cholinergic, serotonergic, and noradrenergic pathways. The peptide has been implicated in cognitive processes, mood regulation, feeding behavior, and neuroprotection, making it a target of interest for neurodegenerative and psychiatric conditions.
Argireline (Acetyl Hexapeptide-8)
Argireline is a synthetic six amino acid peptide (Ac-Glu-Glu-Met-Gln-Arg-Arg-NH2) designed to attenuate neurotransmitter release at the neuromuscular junction. It functions as a competitive inhibitor of the SNARE complex, reducing catecholamine release and potentially diminishing muscle contraction intensity in facial expression muscles. This mechanism provides a topical alternative rationale to botulinum toxin for addressing expression lines, though with markedly lower potency.
Matrixyl (Palmitoyl Pentapeptide-4)
Matrixyl is a lipopeptide composed of a pentapeptide sequence (Lys-Thr-Thr-Lys-Ser) attached to a palmitic acid moiety to enhance dermal penetration. It is proposed to stimulate fibroblast activity and upregulate synthesis of extracellular matrix components including collagen types I and III, fibronectin, and hyaluronic acid. The peptide serves as a matrikine fragment mimetic, signaling tissue remodeling pathways in aged or photodamaged skin.
Matrixyl 3000
Matrixyl 3000 is a proprietary combination of two lipopeptides: palmitoyl tripeptide-1 (Pal-GHK) and palmitoyl tetrapeptide-7 (Pal-GQPR). The formulation is designed to synergistically promote collagen and fibronectin synthesis while reducing interleukin-6 mediated inflammation in dermal fibroblasts. Both peptides carry palmitic acid for enhanced lipid solubility and stratum corneum permeation.
Matrixyl Synthe'6 (Palmitoyl Tripeptide-38)
Palmitoyl tripeptide-38 is a synthetic lipopeptide designed to stimulate synthesis of six major constituents of the dermal matrix: collagen I, III, and IV, fibronectin, hyaluronic acid, and laminin 5. It is proposed to activate transforming growth factor beta (TGF-beta) signaling in fibroblasts, thereby promoting coordinated extracellular matrix assembly. The palmitic acid conjugate enhances dermal bioavailability when applied topically.
SYN-AKE (Dipeptide Diaminobutyroyl Benzylamide Diacetate)
SYN-AKE is a synthetic dipeptide derivative inspired by the venom peptide waglerin-1 from the Temple viper. It acts as a competitive antagonist at nicotinic acetylcholine receptors on the postsynaptic muscle membrane, thereby reducing muscle contraction and potentially smoothing expression lines. The compound is marketed as a topical alternative to botulinum toxin, though with substantially lower receptor affinity and clinical effect.
SNAP-8 (Acetyl Octapeptide-3)
SNAP-8 is an elongated derivative of Argireline, consisting of eight amino acids (Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH2) designed to further inhibit SNARE complex formation and catecholamine-mediated neurotransmitter release. By extending the peptide sequence, the molecule is hypothesized to achieve enhanced binding and greater reduction in muscle contraction intensity in facial expression zones. Like its hexapeptide predecessor, it is positioned as a non-invasive topical anti-wrinkle agent.
Leuphasyl (Pentapeptide-18)
Leuphasyl is a synthetic pentapeptide (Tyr-D-Ala-Gly-Phe-Leu) that mimics the N-terminal sequence of enkephalin and modulates acetylcholine receptor activity at the neuromuscular junction. It is proposed to stabilize the receptor in an inactive conformation, reducing the frequency of muscle fiber contraction without blocking neurotransmission. This mechanism is intended to yield a topical wrinkle-smoothing effect with cosmetic applications.
Vialox (Pentapeptide-3)
Vialox is a synthetic pentapeptide designed to modulate neuromuscular signaling by interfering with acetylcholine receptor activation. The exact sequence is proprietary, but the peptide is marketed as a topical agent to reduce muscle contraction intensity in areas prone to dynamic wrinkles. It is positioned alongside other neuromodulating peptides as a non-invasive alternative to botulinum toxin.
Rigin (Palmitoyl Tetrapeptide-7)
Rigin is a lipopeptide composed of the tetrapeptide sequence Gly-Gln-Pro-Arg conjugated to palmitic acid. It is designed to reduce production of interleukin-6 and other pro-inflammatory cytokines in dermal fibroblasts, thereby mitigating chronic low-grade inflammation associated with skin aging. By modulating the inflammatory microenvironment, the peptide is proposed to support matrix integrity and reduce glycation-induced damage.
Biopeptide CL (Palmitoyl Tripeptide-5)
Palmitoyl Tripeptide-5 is a synthetic lipopeptide consisting of a tripeptide sequence conjugated to palmitic acid to enhance dermal penetration. The peptide is designed to stimulate collagen synthesis by mimicking the activity of thrombospondin-1, a matricellular protein involved in extracellular matrix remodeling. Its therapeutic rationale centers on attenuating photoaging and improving skin elasticity through upregulation of Types I and III collagen in dermal fibroblasts.
Decorinyl (Tripeptide-10 Citrulline)
Decorinyl is a modified tripeptide featuring citrulline substitution, engineered to interact with decorin, a small leucine-rich proteoglycan that regulates collagen fibrillogenesis. The peptide is proposed to enhance decorin production and activity in the dermis, thereby promoting organized collagen assembly and tensile strength. Its development targets improvement of dermal structural integrity in aging and photoaged skin.
Haloxyl (Chrysin + Palmitoyl Peptides)
Haloxyl is a combination ingredient consisting of chrysin, a naturally occurring flavone, and palmitoyl oligopeptides designed to address periorbital hyperpigmentation and edema. The chrysin component is thought to activate enzyme systems involved in bilirubin and hemoglobin clearance, while the palmitoyl peptides enhance dermal penetration and stimulate lymphatic drainage. This dual-mechanism approach targets the appearance of dark circles attributable to both vascular congestion and iron deposition.
Eyeseryl (Acetyl Tetrapeptide-5)
Acetyl Tetrapeptide-5 is a synthetic tetrapeptide modified with an acetyl group to improve stability and cellular uptake. The peptide is proposed to reduce periorbital edema by modulating capillary permeability and enhancing lymphatic drainage, potentially through downregulation of pro-inflammatory cytokines such as interleukin-1. Its application is focused on reduction of under-eye puffiness and fluid accumulation.
Trylagen (Tripeptide-10 Complex)
Trylagen is a proprietary complex incorporating Tripeptide-10 Citrulline along with additional bioactive peptides formulated to support collagen and elastin network architecture. The complex aims to influence multiple stages of extracellular matrix synthesis and assembly, including fibroblast proliferation, procollagen processing, and elastin fiber organization. The therapeutic rationale is directed toward comprehensive photoaging correction and improvement of skin firmness.
Myristoyl Pentapeptide-17
Myristoyl Pentapeptide-17 is a lipopeptide composed of a pentapeptide sequence conjugated to myristic acid to facilitate penetration of the hair follicle and dermal layers. It is marketed primarily for enhancement of eyelash and eyebrow growth through proposed stimulation of keratin gene expression and prolongation of the anagen phase of the hair cycle. The peptide is intended for cosmetic applications related to hair conditioning and growth.
Palmitoyl Tripeptide-1
Palmitoyl Tripeptide-1 is a synthetic lipopeptide comprising a tripeptide linked to palmitic acid, designed to mimic a portion of the Type I collagen molecule. By binding to fibroblast receptors, it is hypothesized to trigger signaling cascades that upregulate collagen and glycosaminoglycan synthesis. This peptide is widely incorporated into topical anti-aging formulations to promote dermal matrix regeneration and reduce the appearance of fine lines.
Copper Peptide (Prezatide Copper Acetate)
Prezatide Copper Acetate is a tripeptide-copper complex, most commonly represented by the sequence Gly-His-Lys bound to a copper ion. Copper peptides are proposed to enhance wound healing, collagen synthesis, and angiogenesis through modulation of matrix metalloproteinases and growth factor activity. The copper moiety is thought to play a critical role in stabilizing the peptide and serving as a cofactor for lysyl oxidase, an enzyme essential for collagen and elastin cross-linking.
Melitane (Acetyl Hexapeptide-1)
Acetyl Hexapeptide-1 is a synthetic hexapeptide designed to stimulate melanin synthesis by acting as an agonist at melanocortin-1 receptors on melanocytes. The acetyl modification is intended to improve peptide stability and cellular permeability. Its therapeutic rationale is to promote tanning and photoprotection through increased melanogenesis, potentially offering a biomimetic alternative to UV exposure for pigmentation enhancement.
Thymogen (Glutamyl-Tryptophan)
Thymogen is a dipeptide consisting of glutamic acid and tryptophan, originally isolated from thymic extracts and proposed to function as an immunomodulatory agent. It is thought to influence T-cell differentiation and cytokine production, thereby enhancing cellular immunity in states of immune suppression or aging-related immunosenescence. The peptide has been investigated primarily in Eastern European and Russian research settings for adjunctive therapy in infections and immune deficiencies.
Thymostimulin (TP-1)
Thymostimulin is a polypeptide extract derived from bovine thymus tissue containing multiple biologically active thymic peptides. It acts on T-lymphocyte maturation and differentiation by mimicking thymic hormone activity. The therapeutic rationale centers on restoring or augmenting immune function in states of T-cell deficiency or immunosuppression.
Splenopentin
Splenopentin is a synthetic pentapeptide (Arg-Lys-Glu-Val-Tyr) corresponding to residues 32 to 36 of the splenic hormone splenin. It modulates immune cell function by enhancing macrophage activity and stimulating antibody production. The therapeutic rationale is to provide targeted immune enhancement without whole-organ extract variability.
Bursin
Bursin is a tripeptide (Lys-His-Gly) originally isolated from the bursa of Fabricius in avian species. It promotes B-lymphocyte differentiation and immunoglobulin production. The therapeutic rationale is to selectively enhance humoral immunity in conditions marked by antibody deficiency.
Tuftsin
Tuftsin is a naturally occurring tetrapeptide (Thr-Lys-Pro-Arg) cleaved from the Fc portion of the heavy chain of immunoglobulin G. It binds to specific receptors on phagocytes, enhancing chemotaxis, phagocytosis, and microbicidal activity. The therapeutic rationale is to augment innate immune responses in immunocompromised states or chronic infections.
Imuthiol (Diethyldithiocarbamate)
Imuthiol is the sodium salt of diethyldithiocarbamate, a small molecule rather than a peptide, historically explored for immune modulation and antiviral properties. It is thought to alter cytokine profiles and scavenge reactive oxygen species. Therapeutic interest has focused on HIV infection and other states of immune dysregulation.
Alpha-MSH
Alpha-melanocyte-stimulating hormone (alpha-MSH) is a 13-amino-acid peptide derived from proopiomelanocortin (POMC). It acts via melanocortin receptors to exert potent anti-inflammatory and immunomodulatory effects, including suppression of proinflammatory cytokines and inhibition of nuclear factor kappa B (NF-kB). Therapeutic interest spans inflammatory and autoimmune disorders.
Beta-Defensin 2
Beta-defensin 2 (hBD-2) is an antimicrobial peptide of approximately 40 amino acids produced by epithelial cells in response to infection or inflammation. It disrupts microbial membranes and also functions as a chemoattractant for immune cells via CCR6 receptor binding. Therapeutic interest includes infection control and immune adjuvant applications.
Beta-Defensin 3
Beta-defensin 3 (hBD-3) is an antimicrobial peptide of approximately 45 amino acids with potent activity against a wide range of pathogens, including antibiotic-resistant strains. It acts by permeabilizing microbial membranes and modulating host immune responses. Therapeutic applications include topical antimicrobial therapy and vaccine adjuvants.
Granulysin
Granulysin is a 15-kDa antimicrobial and cytolytic protein expressed by cytotoxic T lymphocytes and natural killer cells. It disrupts microbial and tumor cell membranes via lipid interactions and induces apoptosis. The therapeutic rationale includes treatment of intracellular infections and cancer immunotherapy.
Serelaxin (Relaxin-2)
Serelaxin is a recombinant form of human relaxin-2, a naturally occurring peptide hormone composed of two chains linked by disulfide bonds. It acts via the relaxin family peptide receptor 1 (RXFP1) to promote vasodilation, inhibit fibrosis, and modulate hemodynamics. The therapeutic rationale targets acute heart failure by improving renal perfusion and reducing vascular resistance.
Carperitide (h-ANP)
Carperitide is a recombinant form of human atrial natriuretic peptide consisting of 28 amino acids. It activates guanylyl cyclase A receptors, increasing intracellular cyclic GMP to promote vasodilation, natriuresis, and diuresis. The peptide reduces cardiac preload and afterload while inhibiting the renin-angiotensin-aldosterone system, providing therapeutic benefit in acute heart failure.
Ularitide (Urodilatin)
Ularitide is a synthetic 32-amino acid peptide analogue of urodilatin, a natriuretic peptide produced in renal tubular cells. It binds to guanylyl cyclase A receptors to increase cyclic GMP, resulting in vasodilation, enhanced sodium excretion, and suppression of the renin-angiotensin-aldosterone system. The peptide was developed for treatment of acute decompensated heart failure with the goal of improving renal function and hemodynamics.
Atrial Natriuretic Peptide (ANP)
Atrial natriuretic peptide is a 28-amino acid endogenous hormone secreted primarily by atrial cardiomyocytes in response to atrial stretch and volume expansion. It binds to natriuretic peptide receptor A, activating guanylyl cyclase to produce cyclic GMP, which mediates vasodilation, natriuresis, and inhibition of aldosterone and renin secretion. ANP plays a critical role in cardiovascular homeostasis and blood pressure regulation.
Brain Natriuretic Peptide (BNP)
Brain natriuretic peptide, despite its name, is a 32-amino acid hormone secreted predominantly by ventricular cardiomyocytes in response to ventricular stretch and pressure overload. It activates guanylyl cyclase A receptors to promote vasodilation, natriuresis, and suppression of the renin-angiotensin-aldosterone and sympathetic nervous systems. BNP and its N-terminal fragment (NT-proBNP) are widely used as diagnostic and prognostic biomarkers in heart failure.
C-type Natriuretic Peptide (CNP)
C-type natriuretic peptide is a 22-amino acid member of the natriuretic peptide family that selectively activates natriuretic peptide receptor B (NPR-B). Unlike ANP and BNP, CNP is produced primarily in vascular endothelium and functions as a paracrine regulator of vascular tone and endothelial permeability with minimal direct renal effects. CNP also plays important roles in bone growth and chondrocyte proliferation through cyclic GMP signaling.
Urocortin 1
Urocortin 1 is a 40-amino acid peptide belonging to the corticotropin-releasing factor (CRF) family. It binds to both CRF receptor 1 and CRF receptor 2 with high affinity, mediating diverse cardiovascular effects including vasodilation, positive inotropy, and cardioprotection. The peptide has demonstrated beneficial hemodynamic properties and anti-inflammatory actions in preclinical models of heart failure and ischemia-reperfusion injury.
Urocortin 2
Urocortin 2 is a 38-amino acid peptide member of the corticotropin-releasing factor family with selective affinity for CRF receptor 2. It exerts cardiovascular effects including coronary and peripheral vasodilation, increased cardiac contractility, and protection against ischemia-reperfusion injury through receptor-mediated cyclic AMP signaling. The selective receptor profile distinguishes it from urocortin 1 and may offer advantages in minimizing stress-axis activation.
Urocortin 3
Urocortin 3, also known as stresscopin, is a 38-amino acid peptide with high selectivity for CRF receptor 2. It produces vasodilation and increases cardiac contractility while exhibiting cardioprotective effects in models of cardiac stress and injury. The selective CRF2 receptor activation avoids hypothalamic-pituitary-adrenal axis stimulation, potentially offering a favorable profile for cardiovascular therapeutics.
Adrenomedullin
Adrenomedullin is a 52-amino acid peptide hormone produced by vascular endothelial and smooth muscle cells with potent vasodilatory and natriuretic properties. It signals through calcitonin receptor-like receptor complexed with receptor activity-modifying proteins, increasing cyclic AMP to promote vasodilation, angiogenesis, and anti-inflammatory effects. Adrenomedullin also modulates vascular permeability and exhibits cardioprotective and renoprotective actions.
Angiotensin (1-7)
Angiotensin (1-7) is a seven-amino acid peptide component of the renin-angiotensin system formed through cleavage of angiotensin II by ACE2 or from angiotensin I by endopeptidases. It binds to the Mas receptor to produce vasodilation, anti-proliferative, anti-fibrotic, and anti-inflammatory effects that generally oppose the actions of angiotensin II. This counter-regulatory arm of the renin-angiotensin system represents a therapeutic target in hypertension, heart failure, and renal disease.
Apelin-13
Apelin-13 is a 13-amino acid endogenous peptide that represents the most potent and abundant isoform of the apelin family. It acts as the ligand for the APJ receptor (also known as the apelin receptor), a G protein-coupled receptor expressed in vascular endothelium, cardiomyocytes, and other tissues. The peptide induces vasodilation, enhances cardiac contractility, and modulates fluid homeostasis, providing therapeutic rationale for heart failure and pulmonary hypertension. Its structure consists of a highly conserved C-terminal sequence critical for receptor binding and biological activity.
Degarelix (Firmagon)
Degarelix is a synthetic decapeptide gonadotropin-releasing hormone (GnRH) receptor antagonist used in the treatment of advanced prostate cancer. Unlike GnRH agonists, degarelix competitively blocks GnRH receptors in the anterior pituitary without causing an initial testosterone surge, achieving rapid suppression of luteinizing hormone and testosterone. This immediate pharmacological castration provides therapeutic benefit in androgen-dependent malignancies. The peptide consists of unnatural amino acids to resist enzymatic degradation and prolong activity.
Triptorelin (Trelstar)
Triptorelin is a synthetic decapeptide analogue of gonadotropin-releasing hormone (GnRH) that functions as a long-acting GnRH agonist. Following an initial stimulatory phase, chronic administration leads to downregulation of pituitary GnRH receptors, resulting in suppression of luteinizing hormone and follicle-stimulating hormone secretion and subsequent reduction in sex steroid production. This mechanism provides therapeutic benefit in hormone-sensitive conditions including advanced prostate cancer, endometriosis, and central precocious puberty. The peptide incorporates amino acid substitutions at positions 6 and 10 to enhance receptor affinity and metabolic stability.
Buserelin (Suprefact)
Buserelin is a synthetic nonapeptide analogue of gonadotropin-releasing hormone (GnRH) that acts as a potent GnRH agonist. It binds with high affinity to pituitary GnRH receptors, initially stimulating gonadotropin release before inducing receptor desensitization and downregulation, ultimately suppressing sex hormone production. The peptide is used primarily in the management of hormone-dependent prostate cancer and endometriosis. Structural modifications include substitution of glycine at position 6 with D-serine and replacement of the C-terminal glycine amide with an ethylamide group to enhance potency and duration of action.
Histrelin (Vantas)
Histrelin is a synthetic nonapeptide analogue of gonadotropin-releasing hormone (GnRH) that functions as a GnRH agonist. The peptide is administered via a subcutaneous implant that delivers continuous drug release over 12 months, inducing initial gonadotropin stimulation followed by sustained receptor downregulation and suppression of testicular androgen production. It is indicated for palliative treatment of advanced prostate cancer and management of central precocious puberty. Amino acid modifications at positions 6 and 10 enhance receptor binding and resistance to peptidase degradation.
Abarelix (Plenaxis)
Abarelix is a synthetic decapeptide that functions as a gonadotropin-releasing hormone (GnRH) receptor antagonist. It competitively blocks pituitary GnRH receptors, producing immediate suppression of luteinizing hormone, follicle-stimulating hormone, and testosterone without the initial surge associated with GnRH agonists. The peptide was developed for treatment of advanced symptomatic prostate cancer in patients who refused surgical castration and were not candidates for GnRH agonist therapy. Its structure incorporates multiple unnatural amino acids to optimize receptor antagonism and pharmacokinetic properties.
Elagolix (Orilissa)
Elagolix is a small molecule non-peptide gonadotropin-releasing hormone (GnRH) receptor antagonist administered orally. While not a peptide itself, it mimics the antagonist action of peptide GnRH blockers by competitively inhibiting endogenous GnRH at pituitary receptors, resulting in dose-dependent suppression of luteinizing hormone, follicle-stimulating hormone, and ovarian sex steroids. It is indicated for management of moderate to severe endometriosis pain and heavy menstrual bleeding associated with uterine fibroids. The oral bioavailability distinguishes it from injectable peptide GnRH antagonists.
Relugolix (Orgovyx)
Relugolix is an orally bioavailable non-peptide gonadotropin-releasing hormone (GnRH) receptor antagonist. Although it is not a peptide, it exerts its therapeutic effect through the same mechanism as peptide GnRH antagonists, competitively blocking pituitary GnRH receptors to suppress gonadotropin and sex steroid production. It is indicated for advanced prostate cancer and, in combination formulation, for management of heavy menstrual bleeding associated with uterine fibroids and moderate to severe endometriosis pain. The oral route of administration offers a distinct advantage over depot peptide formulations.
177Lu-PSMA-617 (Pluvicto)
177Lu-PSMA-617 is a radioligand therapeutic consisting of a small peptide-based ligand targeting prostate-specific membrane antigen (PSMA) conjugated to the beta-emitting radioisotope lutetium-177. The peptide component binds selectively to PSMA, a transmembrane protein highly expressed on prostate cancer cells, enabling targeted delivery of cytotoxic radiation to tumor sites while sparing normal tissues. It is indicated for treatment of metastatic castration-resistant prostate cancer in patients previously treated with androgen receptor pathway inhibition and taxane-based chemotherapy. The targeting moiety is derived from a urea-based peptidomimetic scaffold optimized for PSMA affinity.
Somatostatin (Native)
Somatostatin is a naturally occurring cyclic tetradecapeptide hormone produced by neuroendocrine cells throughout the body, including the hypothalamus, pancreas, and gastrointestinal tract. It functions as a potent inhibitor of growth hormone, insulin, glucagon, and various gastrointestinal hormones by binding to five subtypes of somatostatin receptors (SSTR1-5), which are G protein-coupled receptors. The therapeutic rationale in oncology derives from the expression of somatostatin receptors on neuroendocrine tumors and the peptide's ability to inhibit tumor cell proliferation and hormone secretion. Native somatostatin has an extremely short plasma half-life of 2 to 3 minutes, limiting its clinical utility and necessitating the development of longer-acting synthetic analogues.
Vapreotide
Vapreotide is a synthetic octapeptide analog of somatostatin with enhanced selectivity for somatostatin receptor subtypes 2 and 5. It exerts antisecretory and antiproliferative effects by binding to these receptors on neuroendocrine tumor cells and inhibiting hormone release. The therapeutic rationale centers on control of symptoms associated with vasoactive intestinal peptide secreting tumors and other neuroendocrine malignancies. Its longer half-life compared to native somatostatin allows for sustained receptor occupancy.
Vantictumab
Vantictumab is a fully human monoclonal antibody that targets multiple Frizzled receptors involved in the Wnt signaling pathway. By blocking Frizzled receptors 1, 2, 5, 7, and 8, it inhibits Wnt-driven tumor growth and is designed to target cancer stem cells. The therapeutic rationale is based on dysregulated Wnt signaling in various solid tumors, particularly breast and pancreatic cancers. Inhibition of this pathway may reduce tumor recurrence and metastatic potential.
Tirbanibulin (Klisyri)
Tirbanibulin is a small molecule synthetic peptide mimetic that inhibits tubulin polymerization and disrupts Src kinase signaling pathways. It is applied topically as a 1% ointment to treat actinic keratosis, a precancerous skin condition caused by chronic sun exposure. The dual mechanism targets both the cytoskeleton and oncogenic signaling in hyperproliferative keratinocytes. Its localized application minimizes systemic exposure while achieving targeted antiproliferative effects.
Plitidepsin (Aplidin)
Plitidepsin is a cyclic depsipeptide originally isolated from the Mediterranean tunicate Aplidium albicans and now produced synthetically. It targets the eukaryotic elongation factor 1A2 (eEF1A2), leading to oxidative stress, cell cycle arrest, and apoptosis in malignant cells. The compound has demonstrated activity against multiple myeloma and other hematologic malignancies in preclinical models. Its unique mechanism distinguishes it from conventional chemotherapeutic agents.
Melphalan Flufenamide (Pepaxto)
Melphalan flufenamide is a first-in-class peptide-drug conjugate that links the alkylating agent melphalan to a dipeptide carrier. The dipeptide facilitates cellular uptake via aminopeptidases that are overexpressed in myeloma cells, where intracellular cleavage releases active melphalan. This targeted delivery aims to enhance tumor exposure while reducing systemic toxicity. The compound represents a prodrug strategy to improve the therapeutic index of cytotoxic chemotherapy.
Glucagon Receptor Antagonist Peptides
Glucagon receptor antagonist peptides are a class of molecules designed to block the glucagon receptor and prevent glucagon-mediated hepatic glucose output. These peptides typically consist of modified glucagon analogs with substitutions that convert agonist activity to antagonism. The therapeutic rationale focuses on lowering blood glucose in type 2 diabetes by reducing hepatic gluconeogenesis and glycogenolysis. Structural modifications also enhance metabolic stability and receptor selectivity.
Motilin
Motilin is a 22-amino acid endogenous peptide hormone secreted by enteroendocrine cells in the duodenum and jejunum. It binds to motilin receptors on gastrointestinal smooth muscle and enteric neurons, stimulating phase III migrating motor complexes and promoting gastric emptying. The therapeutic rationale for exogenous motilin or receptor agonists includes treatment of gastroparesis and postoperative ileus. Erythromycin acts as a motilin receptor agonist, demonstrating the clinical relevance of this pathway.
Cholecystokinin (CCK)
Cholecystokinin is an endogenous peptide hormone existing in multiple forms, most commonly as CCK-8 and CCK-33, secreted by I-cells in the duodenum and jejunum. It binds to CCK-1 and CCK-2 receptors to stimulate gallbladder contraction, pancreatic enzyme secretion, and satiety signaling. Therapeutic interest centers on diagnostic imaging applications and potential treatments for obesity and functional gastrointestinal disorders. The peptide also plays neuromodulatory roles in the central nervous system.
Gastrin
Gastrin is an endogenous peptide hormone secreted by G-cells in the gastric antrum and duodenum, existing primarily as gastrin-17 and gastrin-34. It binds to the CCK-2 receptor on parietal and enterochromaffin-like cells, stimulating gastric acid secretion and promoting gastric mucosal growth. Therapeutic applications have focused on gastrin analogs for diagnostic purposes and investigation of gastrin immunotherapy for gastrin-dependent tumors. Dysregulation of gastrin secretion occurs in conditions such as Zollinger-Ellison syndrome and atrophic gastritis.
Peptide YY (PYY 3-36)
Peptide YY 3-36 is a 34-amino acid endogenous peptide hormone secreted by L-cells in the distal small intestine and colon in response to nutrient intake. It acts primarily on the Y2 receptor in the hypothalamus to reduce appetite and slow gastric emptying, functioning as part of the ileal brake mechanism. The therapeutic rationale for exogenous PYY 3-36 administration centers on treatment of obesity through appetite suppression. Circulating levels are reduced in obesity and elevated after bariatric surgery.
Ghrelin Receptor Antagonists
Ghrelin receptor antagonists are a class of peptides and peptidomimetics designed to block the growth hormone secretagogue receptor (GHSR), also known as the ghrelin receptor. Ghrelin is a 28-amino acid orexigenic peptide that stimulates appetite and promotes food intake. By antagonizing GHSR, these agents aim to reduce hunger signals and promote satiety, with therapeutic potential in obesity and metabolic disorders. The class includes both peptide-based molecules and small-molecule antagonists targeting the same receptor.
Guanylin
Guanylin is a 15-amino acid endogenous peptide hormone that activates guanylate cyclase-C (GC-C) receptors on intestinal epithelial cells. Upon binding, it stimulates intracellular cyclic GMP production, which regulates chloride and bicarbonate secretion into the intestinal lumen and promotes fluid secretion. This mechanism enhances intestinal motility and fluid balance. Guanylin functions as a paracrine regulator of intestinal homeostasis and salt-water equilibrium.
Uroguanylin (Dolcanatide)
Uroguanylin is a 16-amino acid endogenous peptide structurally related to guanylin that also activates guanylate cyclase-C receptors in the intestinal epithelium. It regulates fluid and electrolyte secretion in the gut and plays a role in satiety signaling and metabolic homeostasis. The synthetic analog dolcanatide has been developed to mimic uroguanylin's effects with enhanced stability and bioavailability. Like guanylin, uroguanylin increases cyclic GMP levels, promoting intestinal secretion and motility.
Dynorphin A
Dynorphin A is an endogenous opioid peptide of 17 amino acids that preferentially binds to and activates kappa-opioid receptors, though it also has affinity for mu and delta receptors at higher concentrations. It is derived from the precursor protein prodynorphin and plays a complex role in pain modulation, stress responses, and dysphoria. Unlike mu-opioid agonists, kappa receptor activation can produce analgesia without typical euphoria but may induce aversive psychological effects. Dynorphin also has non-opioid actions at high concentrations, including NMDA receptor modulation.
Leu-Enkephalin
Leu-enkephalin is a pentapeptide (Tyr-Gly-Gly-Phe-Leu) that functions as an endogenous opioid agonist with preferential activity at delta-opioid receptors and moderate affinity for mu receptors. It is derived from the precursor proenkephalin and is widely distributed in the central and peripheral nervous systems. The peptide modulates nociceptive transmission and contributes to endogenous analgesia. Leu-enkephalin is rapidly degraded by peptidases, limiting its duration of action.
Met-Enkephalin
Met-enkephalin is a pentapeptide (Tyr-Gly-Gly-Phe-Met) that differs from leu-enkephalin only in its C-terminal amino acid. It acts as an endogenous opioid with preferential delta-opioid receptor activity and also binds mu-opioid receptors. Derived from proenkephalin, met-enkephalin is involved in pain modulation, stress responses, and immune regulation. Like other enkephalins, it is subject to rapid enzymatic degradation by aminopeptidases and enkephalinases.
Endomorphin-1
Endomorphin-1 is a tetrapeptide (Tyr-Pro-Trp-Phe) that exhibits highly selective agonist activity at the mu-opioid receptor, the primary target for analgesic opioids. It is one of two endomorphin isoforms and represents the most selective endogenous mu-opioid ligand identified to date. Endomorphin-1 is distributed in pain-processing regions of the central nervous system. Its selective mu receptor activity theoretically offers potent analgesia with a potentially different side effect profile compared to less selective opioids.
Endomorphin-2
Endomorphin-2 is a tetrapeptide (Tyr-Pro-Phe-Phe) that, like endomorphin-1, demonstrates highly selective agonism at mu-opioid receptors. The two endomorphins differ by a single amino acid but share similar receptor selectivity and analgesic properties. Endomorphin-2 is found in spinal and supraspinal sites involved in nociception. Its unique selectivity profile has generated interest in developing analogs that retain efficacy while minimizing respiratory depression and other opioid side effects.
Nociceptin / Orphanin FQ
Nociceptin, also known as orphanin FQ, is a 17-amino acid peptide that acts as the endogenous ligand for the nociceptin/orphanin FQ peptide (NOP) receptor, a member of the opioid receptor family with distinct pharmacology. Despite structural similarity to dynorphin A, nociceptin does not bind classical opioid receptors. Its effects on pain are complex and context-dependent, producing analgesia at the spinal level but pronociceptive or hyperalgesic effects at supraspinal sites. The peptide also modulates stress, anxiety, and reward pathways.
Conantokin-G
Conantokin-G is a 17-amino acid peptide originally isolated from the venom of the cone snail Conus geographus. It acts as a selective antagonist of N-methyl-D-aspartate (NMDA) receptors containing the NR2B subunit, which are implicated in chronic pain, neuropathic pain, and central sensitization. The peptide contains gamma-carboxyglutamic acid residues that are critical for its activity and metal ion binding. Conantokin-G represents a novel class of non-opioid analgesics targeting glutamatergic neurotransmission.
Dermorphin
Dermorphin is a heptapeptide opioid agonist originally isolated from the skin of South American Phyllomedusa frogs. It exhibits high selectivity and affinity for the mu-opioid receptor, with potency approximately 30 to 40 times greater than morphine in animal models. The unique D-alanine residue at position 2 confers resistance to peptidase degradation and contributes to its prolonged analgesic activity. Its potent receptor binding has made it a valuable research tool for studying opioid receptor pharmacology.
Deltorphin
Deltorphin is a heptapeptide opioid agonist also derived from Phyllomedusa frog skin secretions, characterized by high selectivity for delta-opioid receptors. Like dermorphin, it contains an unusual D-amino acid residue that enhances metabolic stability and receptor affinity. Deltorphin exhibits analgesic properties distinct from mu-opioid agonists, with reduced respiratory depression and addiction liability in animal models. It has served as a pharmacological tool to elucidate delta-opioid receptor physiology and potential therapeutic roles.
Neuropeptide FF
Neuropeptide FF (NPFF) is an octapeptide belonging to the RFamide family, characterized by an arginine-phenylalanine-amide motif at the C-terminus. It acts on two G protein-coupled receptors, NPFF1 and NPFF2, and modulates opioid-induced analgesia, tolerance, and hyperalgesia. NPFF is widely distributed in the central nervous system and participates in pain modulation, opioid tolerance mechanisms, and cardiovascular regulation. Its dual role as both a pronociceptive and anti-opioid peptide has generated interest in targeting its receptors for chronic pain management.
Magainin 2
Magainin 2 is a 23-amino acid antimicrobial peptide originally isolated from the skin of the African clawed frog Xenopus laevis. It exerts broad-spectrum antimicrobial activity through membrane disruption, forming pores in bacterial membranes while exhibiting relative selectivity over mammalian cells. Magainin 2 belongs to the alpha-helical cationic antimicrobial peptide family and has served as a template for numerous synthetic analogs. Its mechanism of action, which is distinct from conventional antibiotics, offers potential against multidrug-resistant pathogens.
Pexiganan (MSI-78)
Pexiganan is a 22-amino acid synthetic analog of magainin 2 designed to enhance antimicrobial potency and proteolytic stability. It disrupts bacterial membranes through electrostatic interaction and pore formation, demonstrating broad-spectrum activity against gram-positive and gram-negative organisms, including methicillin-resistant Staphylococcus aureus. Pexiganan was developed as a topical agent for infected diabetic foot ulcers, leveraging its rapid bactericidal action and low resistance potential. Structural modifications from the parent magainin sequence improve its pharmacological profile for clinical use.
Omiganan
Omiganan is a synthetic 12-amino acid cationic antimicrobial peptide derived from indolicidin, a naturally occurring peptide from bovine neutrophils. It acts by disrupting microbial membranes and demonstrates activity against bacteria, fungi, and some viruses. Omiganan was developed as a topical agent to prevent catheter-related bloodstream infections through its broad-spectrum antimicrobial properties. Its small size and potent activity made it a candidate for preventing biofilm formation on medical devices.
Iseganan (IB-367)
Iseganan is a 17-amino acid synthetic analog of protegrin, a naturally occurring antimicrobial peptide found in porcine leukocytes. It disrupts microbial cell membranes via a beta-sheet structure stabilized by disulfide bonds, conferring broad-spectrum activity against bacteria, fungi, and some viruses. Iseganan was developed primarily as an oral rinse to prevent ventilator-associated pneumonia and oral mucositis in immunocompromised patients. Its rapid microbicidal action and low systemic absorption profile supported its formulation for topical oral use.
Defensin HNP-1
Human neutrophil peptide 1 (HNP-1) is a 30-amino acid alpha-defensin produced by neutrophils as part of the innate immune response. It contains three stabilizing disulfide bonds and forms amphipathic structures that disrupt microbial membranes through electrostatic and hydrophobic interactions. HNP-1 exhibits antimicrobial activity against bacteria, fungi, and enveloped viruses, and also modulates immune cell function and inflammatory responses. As an endogenous peptide, it has been studied for potential therapeutic augmentation in immunocompromised states and chronic infections.
Alpha-Defensin 5
Alpha-defensin 5 (HD5) is a 32-amino acid cationic peptide predominantly expressed by Paneth cells in the small intestinal crypts. It contains three disulfide bonds that stabilize its beta-sheet structure and enable membrane disruption of bacteria, fungi, and some viruses. HD5 plays a critical role in maintaining intestinal homeostasis by regulating gut microbiota composition and protecting the epithelial barrier. Altered HD5 expression has been implicated in inflammatory bowel disease, necrotizing enterocolitis, and susceptibility to enteric infections.
Lactoferricin
Lactoferricin is a cationic antimicrobial peptide derived from pepsin-mediated cleavage of lactoferrin, an iron-binding glycoprotein found in milk and mucosal secretions. The most studied variant, bovine lactoferricin B, is a 25-amino acid peptide that disrupts microbial membranes and chelates iron, contributing to its broad-spectrum antimicrobial activity. Lactoferricin exhibits antibacterial, antifungal, antiviral, and antiparasitic properties, along with immunomodulatory effects. Its natural origin and multifunctional activity have generated interest in food preservation, oral health, and topical antimicrobial applications.
Nisin
Nisin is a 34-amino acid polycyclic antibacterial peptide (lantibiotic) produced by Lactococcus lactis. It disrupts bacterial cell wall synthesis and forms pores in cell membranes by binding to lipid II, a precursor essential for peptidoglycan assembly. Its activity is primarily directed against Gram-positive bacteria, making it valuable in food preservation applications. The peptide contains unusual amino acids including lanthionine and beta-methyllanthionine, which confer structural stability and antimicrobial potency.
Gramicidin S
Gramicidin S is a cyclic decapeptide antibiotic isolated from Bacillus brevis, consisting of two identical pentapeptide sequences joined in a ring structure. The peptide exerts antimicrobial activity by disrupting bacterial cell membrane integrity through interaction with phospholipid bilayers, leading to leakage of cellular contents. Its amphipathic beta-sheet conformation enables selective insertion into bacterial membranes. The compound demonstrates broad-spectrum activity against both Gram-positive and Gram-negative organisms.
Polymyxin B
Polymyxin B is a cyclic lipopeptide antibiotic derived from Bacillus polymyxa, consisting of a heptapeptide ring and a tripeptide side chain acylated with a fatty acid tail. The molecule binds to lipopolysaccharide in the outer membrane of Gram-negative bacteria, causing membrane permeabilization and cell death. Its cationic residues interact electrostatically with anionic phosphate groups on lipid A. Polymyxin B is reserved for serious infections caused by multidrug-resistant Gram-negative pathogens when other options are unavailable.
Colistin (Polymyxin E)
Colistin, also known as polymyxin E, is a cyclic polypeptide antibiotic structurally similar to polymyxin B, produced by Paenibacillus polymyxa. It disrupts the bacterial cell membrane by binding to lipopolysaccharide and displacing divalent cations, leading to increased permeability and cell lysis. The compound is administered as colistimethate sodium, an inactive prodrug that is hydrolyzed in vivo to the active colistin base. Its spectrum targets Gram-negative bacteria, particularly Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae.
Indolicidin
Indolicidin is a 13-amino acid antimicrobial peptide derived from bovine neutrophils, characterized by a high tryptophan content (five residues). It exerts antimicrobial activity through multiple mechanisms, including membrane disruption, DNA binding, and inhibition of intracellular processes. The peptide adopts an extended wedge-shaped conformation that facilitates insertion into lipid bilayers. Indolicidin demonstrates activity against bacteria, fungi, and certain protozoa, though its clinical development has been limited by cytotoxicity.
PTH (1-34) Analogs
PTH (1-34) analogs, including teriparatide and abaloparatide, are synthetic peptides corresponding to the 34 N-terminal amino acids of human parathyroid hormone. These agents bind to the PTH1 receptor on osteoblasts and osteocytes, stimulating bone formation through activation of intracellular signaling pathways including cyclic AMP and protein kinase A. Intermittent administration preferentially stimulates osteoblastic bone formation over osteoclastic resorption, increasing bone mass and reducing fracture risk. The anabolic effect distinguishes these agents from antiresorptive therapies such as bisphosphonates.
Sclerostin Antibodies (Romosozumab)
Romosozumab is a humanized monoclonal antibody that binds and inhibits sclerostin, a glycoprotein produced by osteocytes that negatively regulates the Wnt signaling pathway. By blocking sclerostin, romosozumab increases Wnt pathway activity in osteoblasts, simultaneously promoting bone formation and reducing bone resorption. This dual mechanism produces rapid and substantial increases in bone mineral density. The antibody is composed of two heavy and two light immunoglobulin chains in a standard IgG2 configuration.
Osteogenic Growth Peptide (OGP)
Osteogenic Growth Peptide is a naturally occurring 14-amino acid peptide identified in serum that promotes osteoblast proliferation and differentiation. The peptide activates the MAP kinase signaling pathway and stimulates collagen synthesis in bone-forming cells. OGP also demonstrates hematopoietic activity, influencing stem cell differentiation in the bone marrow microenvironment. Synthetic analogs have been developed to enhance stability and receptor affinity for potential therapeutic applications in osteoporosis and fracture healing.
BMP-2 (Bone Morphogenetic Protein-2)
BMP-2 is a member of the transforming growth factor-beta superfamily, consisting of a homodimeric protein with each monomer containing approximately 114 amino acids in its mature form. The protein binds to type I and type II serine/threonine kinase receptors on mesenchymal stem cells, activating SMAD-dependent signaling pathways that induce osteoblastic differentiation and bone formation. Recombinant human BMP-2 is delivered on an absorbable collagen sponge carrier to provide sustained local release at the site of intended bone growth. The molecule is a potent osteoinductive agent capable of inducing ectopic bone formation when implanted in soft tissue.
BMP-7 (Osteogenic Protein-1)
BMP-7, also known as osteogenic protein-1 (OP-1), is a member of the bone morphogenetic protein family with a mature homodimeric structure of approximately 139 amino acids per monomer. Like other BMPs, it signals through serine/threonine kinase receptors to activate SMAD transcription factors, promoting differentiation of mesenchymal cells into osteoblasts and chondrocytes. The recombinant form is delivered on a bovine collagen matrix to provide localized, sustained release. BMP-7 also exhibits renoprotective effects in preclinical models, though clinical development in nephrology has not advanced.
Calcitonin Gene-Related Peptide (CGRP)
Calcitonin gene-related peptide is a 37-amino acid neuropeptide produced by alternative splicing of the calcitonin gene. CGRP acts as a potent vasodilator and plays a key role in migraine pathophysiology by binding to CGRP receptors on vascular smooth muscle and trigeminal nerve endings. While CGRP itself has effects on bone metabolism through regulation of osteoblast and osteoclast activity, therapeutic development has focused primarily on antagonizing CGRP signaling rather than administering the peptide. The peptide's role in bone includes modulation of bone formation and vascular coupling in skeletal tissue.
Gonadotropin Releasing Hormone (GnRH) Agonists
Gonadotropin-releasing hormone agonists are synthetic decapeptide analogues of native GnRH that initially stimulate and then suppress gonadotropin secretion from the pituitary gland. Following initial receptor activation, continuous GnRH agonist exposure leads to receptor downregulation and reversible suppression of the hypothalamic-pituitary-gonadal axis, reducing sex steroid production. Approved formulations include leuprolide, goserelin, and triptorelin, used primarily in hormone-sensitive cancers and reproductive medicine. The longevity rationale derives from theoretical models linking reduced reproductive signaling to extended lifespan observed in model organisms, though this remains speculative in humans.
Klotho Peptide
Klotho is a transmembrane protein of approximately 1012 amino acids that exists in membrane-bound and secreted forms, with the soluble ectodomain functioning as a circulating factor. Klotho acts as a coreceptor for fibroblast growth factor 23 in phosphate metabolism and independently influences insulin signaling, oxidative stress, and cellular senescence pathways. Reduced klotho expression is associated with accelerated aging phenotypes in mice, while overexpression extends lifespan in rodent models. Therapeutic development focuses on peptide fragments or recombinant forms to replicate klotho's protective effects in age-related conditions.
Sirtuin-Activating Peptides
Sirtuin-activating peptides represent a class of investigational compounds designed to enhance the enzymatic activity of sirtuins, a family of NAD-dependent deacetylases implicated in longevity and metabolic regulation. These peptides aim to mimic or potentiate the effects of caloric restriction by modulating histone deacetylation, mitochondrial biogenesis, and stress resistance pathways. While small molecule sirtuin activators such as resveratrol analogues have received more research attention, peptide-based approaches remain in early discovery phases. The therapeutic rationale centers on reproducing the lifespan-extending effects of sirtuin overexpression observed in lower organisms.
Mitochondrial-Targeted Peptides (MTP)
Mitochondrial-targeted peptides are short synthetic sequences, typically 2 to 8 amino acids, designed to localize to mitochondria and protect against oxidative damage and organelle dysfunction. Representative compounds include SS-31 (elamipretide), a tetrapeptide that associates with cardiolipin in the inner mitochondrial membrane to reduce reactive oxygen species and improve electron transport chain efficiency. These peptides aim to address mitochondrial dysfunction implicated in aging, heart failure, neurodegenerative disease, and ischemia-reperfusion injury. The longevity application is based on the mitochondrial theory of aging and evidence that mitochondrial protection extends lifespan in model organisms.
Thymulin (Zn-FTS)
Thymulin is a nonapeptide hormone secreted by thymic epithelial cells that requires zinc for biological activity and is also referred to as facteur thymique serique or FTS. The peptide modulates T-cell differentiation and immune function, with circulating levels declining with age in parallel with thymic involution. The therapeutic hypothesis proposes that thymulin supplementation may restore immune competence in aging individuals and counteract immunosenescence. Synthetic zinc-thymulin complexes have been investigated as potential immunorestorative agents in experimental settings.
Gerontin (Pineal Gland Extract)
Gerontin refers to peptide fractions derived from pineal gland extracts studied primarily in Russian gerontology research. These preparations are hypothesized to contain bioactive peptides that regulate circadian rhythms, antioxidant defenses, and neuroendocrine aging processes. The pineal gland's role in melatonin synthesis and circadian coordination provides a biological rationale for investigating pineal-derived factors in aging. Gerontin formulations are not standardized, and active components have not been fully characterized by modern analytical methods.
Vilon (Lys-Glu)
Vilon is a synthetic dipeptide consisting of lysine and glutamic acid (Lys-Glu) developed as part of the Khavinson bioregulator peptide research program. The peptide is proposed to interact with DNA regulatory regions to modulate gene expression related to immune function and cellular repair. Vilon has been studied primarily in Russian research for immunomodulation and potential geroprotective properties. The mechanism is postulated to involve epigenetic regulation, though detailed molecular characterization remains incomplete.
Bioregulator Peptides (Khavinson)
Bioregulator peptides are a class of short synthetic peptides, typically 2 to 4 amino acids in length, developed by Russian researcher Vladimir Khavinson based on sequences derived from organ-specific tissues. These peptides are theorized to exert tissue-specific regulatory effects by interacting with chromatin to modulate gene expression and restore age-related functional declines. Examples include thymus-derived peptides (Thymalin), pineal peptides (Epithalamin), and vascular peptides. The underlying hypothesis is that peptide bioregulators can reverse or slow aging by re-establishing youthful patterns of protein synthesis in target organs.
IGF-1 LR3 (Long-Arg3)
IGF-1 LR3 is a synthetic analogue of insulin-like growth factor 1 with an N-terminal extension of 13 amino acids and a substitution of arginine for glutamic acid at position 3. These modifications reduce binding to IGF-binding proteins, resulting in an extended half-life and increased bioavailability compared to native IGF-1. The peptide promotes anabolic processes including muscle protein synthesis, glucose uptake, and cellular proliferation. IGF-1 LR3 is not approved for human use and is primarily available as a research reagent, though it is sometimes misused in athletic and bodybuilding contexts.
IGF-1 DES (1-3)
IGF-1 DES (1-3) is a truncated analogue of insulin-like growth factor 1 lacking the first three N-terminal amino acids (glycine-proline-glutamate). This structural modification prevents binding to IGF binding proteins in serum, resulting in a shorter half-life but significantly increased potency at the IGF-1 receptor compared to native IGF-1. The peptide is hypothesized to promote localized muscle hypertrophy and tissue repair through enhanced receptor activation in target tissues.
MGF (Mechano Growth Factor)
Mechano Growth Factor is a splice variant of the IGF-1 gene expressed in response to mechanical stress on muscle tissue. The peptide contains a unique C-terminal domain resulting from alternative splicing that distinguishes it from systemic IGF-1. MGF is proposed to act locally in skeletal muscle to activate satellite cells and promote muscle fiber repair and hypertrophy following mechanical loading or injury.
PEG-MGF
PEG-MGF is a pegylated derivative of Mechano Growth Factor designed to extend systemic half-life through the addition of polyethylene glycol moieties. Pegylation reduces renal clearance and proteolytic degradation, theoretically allowing for less frequent dosing and broader tissue distribution compared to unmodified MGF. The modified peptide retains the proposed satellite cell activation properties of native MGF.
Follistatin-344
Follistatin-344 is a 344-amino acid glycoprotein that functions as a binding protein and endogenous antagonist of myostatin and other members of the TGF-beta superfamily. By sequestering myostatin, follistatin removes inhibitory signals that limit skeletal muscle growth, thereby permitting increased muscle fiber hypertrophy and hyperplasia. The peptide also modulates activin and bone morphogenetic protein signaling pathways.
ACE-031 (Ramatercept)
ACE-031 is a recombinant fusion protein combining the extracellular domain of the activin receptor type IIB with a human IgG1 Fc domain. This soluble receptor acts as a decoy to bind and neutralize myostatin, activin, and other negative regulators of muscle growth. By inhibiting these TGF-beta superfamily ligands, ACE-031 was designed to promote muscle hypertrophy in conditions characterized by muscle wasting.
Nafarelin (Synarel)
Nafarelin is a synthetic decapeptide analogue of gonadotropin-releasing hormone (GnRH) with substitutions at positions 6 and 10 that enhance receptor affinity and metabolic stability. Chronic administration leads to downregulation of pituitary GnRH receptors and suppression of gonadotropin secretion, resulting in a hypoestrogenic state. This mechanism is therapeutically exploited in conditions requiring ovarian suppression, including endometriosis and central precocious puberty.
Choriogonadotropin Alfa (Ovidrel)
Choriogonadotropin alfa is a recombinant human chorionic gonadotropin produced in Chinese hamster ovary cells with identical amino acid sequence to endogenous hCG. The 237-amino acid heterodimeric glycoprotein binds the LH/hCG receptor on ovarian granulosa and theca cells to trigger final oocyte maturation and ovulation. It is used in assisted reproductive technology protocols to time oocyte retrieval and support luteal phase progesterone production.
Follitropin Alfa (Gonal-F)
Follitropin alfa is a recombinant human follicle-stimulating hormone produced in Chinese hamster ovary cells, consisting of a heterodimeric glycoprotein with 92-amino acid alpha and 111-amino acid beta subunits. The peptide binds FSH receptors on ovarian granulosa cells to stimulate follicular development, estradiol synthesis, and oocyte maturation. It is employed in ovulation induction and controlled ovarian stimulation for assisted reproductive technologies.
Menotropin (Menopur)
Menotropin is a purified preparation of human menopausal gonadotropins extracted from the urine of postmenopausal women, containing both follicle-stimulating hormone and luteinizing hormone activity in approximately equal proportions. The combination of FSH and LH bioactivity stimulates follicular recruitment, granulosa cell proliferation, and steroidogenesis in ovarian theca cells. It is indicated for ovulation induction in anovulatory infertility and controlled ovarian hyperstimulation in assisted reproduction.
Corifollitropin Alfa (Elonva)
Corifollitropin alfa is a recombinant long-acting FSH analogue created by fusing the C-terminal peptide of the hCG beta subunit to the FSH beta chain. This structural modification extends the elimination half-life to approximately 70 hours, enabling a single injection to sustain follicular stimulation for seven days. The agent is designed to simplify controlled ovarian stimulation protocols by replacing the first week of daily FSH injections in IVF cycles.
Cetrorelix (Cetrotide) Analog
Cetrorelix is a synthetic decapeptide analog of gonadotropin-releasing hormone (GnRH) that acts as a competitive GnRH receptor antagonist. By binding to pituitary GnRH receptors, it rapidly suppresses luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion without the initial agonist flare seen with GnRH agonists. This property makes it valuable for controlled ovarian stimulation protocols, where prevention of premature LH surges is critical for optimizing oocyte retrieval timing.
Peginesatide (Omontys)
Peginesatide is a synthetic pegylated peptide-based erythropoiesis-stimulating agent (ESA) consisting of two 21-amino acid chains linked to polyethylene glycol. Unlike recombinant erythropoietin, it contains no erythropoietin sequence homology yet activates the erythropoietin receptor to stimulate red blood cell production. The pegylation confers a prolonged half-life, enabling once-monthly dosing in dialysis-dependent chronic kidney disease.
Eltrombopag Peptide Mimetics
Eltrombopag is a small-molecule, non-peptide thrombopoietin receptor agonist that binds to the transmembrane domain of the thrombopoietin receptor, distinct from the natural ligand binding site. While not itself a peptide, it mimics thrombopoietin signaling to stimulate megakaryocyte proliferation and platelet production. The oral bioavailability of this synthetic agent addresses limitations of recombinant thrombopoietin peptides, which face immunogenicity challenges.
Hepcidin
Hepcidin is a 25-amino acid endogenous peptide hormone produced primarily by hepatocytes that serves as the master regulator of systemic iron homeostasis. It binds to ferroportin, the sole known cellular iron exporter, inducing its internalization and degradation, thereby blocking iron release from enterocytes, macrophages, and hepatocytes. Therapeutic hepcidin agonists and antagonists are being developed to treat iron overload disorders and anemia of chronic disease, respectively.
Thrombopoietin (TPO)
Thrombopoietin is a 332-amino acid endogenous glycoprotein hormone and the primary physiologic regulator of megakaryopoiesis and platelet production. It binds to the c-Mpl receptor on megakaryocyte progenitors and mature megakaryocytes, stimulating their proliferation, differentiation, and platelet release. Recombinant TPO and pegylated recombinant megakaryocyte growth and development factor (PEG-rHuMGDF) were developed but abandoned after clinical trials revealed antibody-mediated thrombocytopenia.
Gadopentetate Peptide Conjugates
Gadopentetate peptide conjugates consist of the gadolinium-based contrast agent gadopentetate dimeglumine chemically linked to targeting peptides designed to bind specific tissue markers or receptors. These hybrid molecules combine the MRI contrast properties of chelated gadolinium with the molecular specificity of peptides to enable targeted imaging of tumors, inflammatory lesions, or vascular pathology. Various peptide motifs including RGD sequences and somatostatin analogs have been conjugated to gadolinium chelates for preclinical evaluation.
DOTATATE (Ga-68)
Gallium-68 DOTATATE is a radiolabeled somatostatin analog consisting of an octapeptide (Tyr3-octreotate) conjugated to the macrocyclic chelator DOTA, which binds the positron-emitting radioisotope gallium-68. It exhibits high affinity for somatostatin receptor subtype 2, which is overexpressed on neuroendocrine tumor cells, enabling PET imaging of these malignancies. The 68-minute half-life of gallium-68 and the rapid pharmacokinetics of the peptide provide excellent tumor-to-background ratios within 1 to 2 hours post-injection.
Bombesin Analog Tracers
Bombesin analog tracers are synthetic peptides based on the 14-amino acid amphibian peptide bombesin or its mammalian counterpart gastrin-releasing peptide (GRP), radiolabeled for molecular imaging. These analogs bind to GRP receptors, which are overexpressed in prostate, breast, and small cell lung cancers, enabling tumor visualization via PET or SPECT imaging. Various radionuclides including gallium-68, fluorine-18, technetium-99m, and copper-64 have been conjugated to bombesin antagonist and agonist peptides.
RGD Peptide Tracers
RGD peptide tracers are short synthetic peptides containing the arginine-glycine-aspartic acid (RGD) tripeptide sequence, which binds to integrin receptors, particularly alphavbeta3, conjugated to positron or gamma-emitting radioisotopes. Alphavbeta3 integrin is upregulated on angiogenic endothelium and many cancer cells, making RGD tracers useful for imaging tumor angiogenesis, metastatic disease, and potentially cardiovascular pathology. Cyclic RGD peptides and multimeric constructs have been developed to improve binding affinity and tumor retention.